Nedarim 42b - Rights to a Field during Shemitta

The Ran seems to understand that although the owner retains ownership of his field during shemittah, he must allow people to enter in order to pick fruits. However, the right of entry that people have on his field is only for the purpose of obtaining the fruit, therefore if they can get access to the fruit without entering the field they do not have a right to enter (As a side point, tosafos seems to indicate that the right of entry is not limited to just picking the fruit, but they can enter and eat the fruit in his field - i don't know if the Ran would argue with that).

However, in a situation where the trees are near the edge of the field so that there is full access without entering the field, the Rosh is not sure whether the issur to enter the field only applies to a mudar hana'ah, or does it apply to all and would constitute trespassing. The second tzad that others may enter, and it is only a mudar hana'ah that cannot enter, is not so clear. If the mitzvah of shemittah allows for complete entry to pick fruits even when they can be obtained from outside the field, the madir should not have the power to assur this on the mudar. And if the mitzvah of shemittah only allows for entry when it is necessary to pick the fruits, why can the owner not block people from entering because of trespassing? Perhaps the Rosh means that although the mitzvah of shemittah does not allow for entry when the fruits can be obtained from outside, we can assume that if it is easier for people to obtain the fruits by entering the owner would not be makpid. Therefore if the owner would put up a sign indicating that he is makpid, it would be assur to enter to take the fruits that can be obtained from the outside even according to the second tzad of the Rosh, just like a mudar hana'ah cannot enter.

Nedarim 41b - Providing Refuah for a Choleh

The Ran explains that a doctor is allowed to provide refuah to a choleh, even though there is a neder forbidding him to provide benefit to the choleh, since: 1. it is a mizvah. 2. he is using the medicine of the choleh himself, and therefore is not literally giving him anything. This is even permitted when there is someone else available to heal the choleh, because it could be that this doctor will be the one who will be zocheh to be successful so we consider it as if there is no other doctor available. But, a veterinarian cannot heal the animal of the mudar since he is benefiting him. However, the Ran says that if there is no other vet to heal the animal, the madir can do it because it is a mitzvah of hashavas aveida. This implies that if there are other veterinarians around, there is not a mitzvah of hashavas aveida. The rationale is that if there are other people to do it, since this individual is forbidden with a neder to provide benefit, the mitzvah is incumbent upon the others who are not forbidden with this neder, and once others are able and available to do it, it is no longer an "aveida" so there is no mitzvah on him. But if there is no one else available to do it, then there is a mitzvah of hashavas aveida and even the individual who is assur b'neder can do return the object or heal the animal.
The Ya'avetz understands that there isn't any machlokes between the Ran and Rosh, since the Rosh is talking when there is another vet available to do it and therefore not a mitzvah of hashavas aveida (although the language of the Rosh sounds more that there is no mitzvah to heal someones animal). R' Akiva Eiger asks, that by returning an aveida the sevara of mitzvah is not the primary heter (although the nimukei yosef uses the sevara of mitzvah to explain why the tircha is allowed), rather the main heter is that it is saving the object from a loss and mavriach ari is not hana'ah. This is only applicable to a lost object, but healing his animal is tantamount to feeding it which is considered a hana'ah and not just saving him from a loss, so it should be assur even if there is no one else to do it? Perhaps the Ran considered the healing of an animal to also be saving him from a loss, since the disease is threatening the animal.

Nedarim 40b - A Gadol Visiting a Kattan

R' Moshe (y.d. 1:222) has a teshuva to the chechnove rebbe where he discusses an important question. How can there be a mitzvah of a gadol to visit a kattan (and presumably to clean the room if needed like the talmidim of r' akiva); shouldn't there be an exemption of zaken v'aino l'fi k'vodo? The Rebbe wanted to answer that whenever it is recognizable that one is involved in a mitzvah there is no exemption of zaken v'eino l'fi k'vodo. Although he doesn't quoted it, it is based on a biur halacha (250) who points to a gemara in kiddushin (as does r' moshe) that r' nachman built a fence in public to fulfill the mitzvah of ma'akeh because it was clear to all that he was doing it for a mitzvah and did not have an exemption of zaken v'aino l'fi k'vodo. However, R' Moshe holds that this is only true regarding mitzvos bein adam l'makom, as we find by r' nachman, as we find by dovid dancing, and as we find by the amoraim who would make shabbos preparations themselves. But, by bein adam l'chaveiro we learn from hashavas aveida that even if it is clear that you are doing a mitzvah, you are not required to do something for someone else that you would not do for yourself. Nevertheless, when it comes to bikur cholim r' moshe concludes that one cannot make a cheshbon to protect degrading themselves at the expense of physical suffering of someone else. Therefore, even a kattan is required to visit a gadol and degrade himself to tend to the choleh's needs to help alleviate the physical pain of the choleh. But generally, if one would not do it for themselves they do not have to do it for someone else, even if it is clear that it is being done for a mitzvah.

charging for a mitzvah

בענין תשלומין על מצווה
בפשטות א"א לקחת שכר על כל מצווה, ועיין במהרש"א ח"א ל"ח ע"ב שזה דבר פשוט. והנראה בביאורו - שחייב שהאדם יעשה המצווה מכח ציווי של התורה ולא בגלל תשלום של שכר, דזה עיקר עניין המצווה שתעשה לשם רצון השם.
בכתובות התבאר לנו ההלכות של קיחת שכר כדי לדון דין, ונתבאר שם שלקחת שכר בטלה דמוכח כההוא אומורא שטעם יינות לפרנסתו, מותר לכתחילה, ושכר בטלה דלא מוכח מות בדיעבד, ושכר על הדין עצמו אסור ממש. עוד התבאר שם שהדיינים או המלמדים שהציבור שכרו אותם שידונו כל היום, פשוט שלוקחים שכר מהציבור. והביאור נ"ל ששם לא לוקחים השכר למצווה, דהיינו שהם לא אומרים שאילולא השכר לא היו מקיימים מצוות, אלא שצריכים כדי מחייתן ולכן מוכרחים לקחת שכר. הגע עצמך שזה שנעשה מלמד תינוקות, הרי אם לכסף הוא נושא עיניו עדיף היה לו להיות עורך דין או רואה חשבון, אלא שרצונו העמוק הוא ללמוד וללמד אלא שצריך לפרנסה ולכן לוקח שכר אפילו לכתחילה.
ועיין בסמ"ע רס"ד סקי"ט דמבואר שם דאם העושה המצווה זהו עבודתו וכך עושה כסף למחייתו, מותר לו לקחת שכר אפילו למצווה. והדוגמא שם הוי באחד שבורח מבית האסורים ומבקש מספן שיעבירנו את הנהר, נותן לו שכרו, ומחדש הסמ"ע שאפילו שאין שם שכר בטלה דהיינו שלא היה לספן אחרים שרצו לשוכרו, עדיין מותר לספן לקחת השכר כיוון שזהו פרנסתו. ע"ש. ושוב נ"ל הביאור שכל עוד שזה פרנסתו נמצא שלוקח השכר כי זהו עבודתו ולקיחת השכר לא אומרת לנו שאילולא השכר לא היה מקיים המצווה ולכן מותר.
איברא דהסוגיא לא נשלמה בלי ביאור מחלוקת הראשונים אי מותר לקחת שכר על מעשה הצלה (אפילו אי לא הוי עבודתו) , עיין בזה בסוגיא קידושין ח' ע"בבבעית הגמרא כלב רץ אחריה מהו. המעיין שם ברשב"א ובריטב"א ובמאירי וברב אלחנן ימצא שיש מ"ח ראשונים אי מותר לקחת שכר על מעשה הצלה. ראית הרא"ש מהמציל את עצמו בנכסי חבירו שחייב לשלם אחר שניצול, ומזה לומד שכל מציל ל"צ לעשות בחינם, ונראה ברור שלא יכול לקחת שכר על הטירחא של ההצלה אך יכול לקחת שכר על מה שנפסד בממונו, שס"ל לרא"ש שיש רק חיוב לטרוח בחינם ולא להפסיד ממון בחינם. והרב אלחנן מביא עוד ראיה מכתובות נ"ט שהאב כופה את גרושתו להניק אך חייב לשלם לה שכר אף שהתינוק בסכנה והיא מצילתו (ושוב צריך לומר שמשלם על ממון שחסרה). והמאירי והרשב"א סוברים שצריך להציל בחינם ומה שהמציל חבירו בממון חבירו חייב לשלם הוא כיוון שאין המצווה על ממונו אלא על גוף המציל ולכן שם אין המציל לפנינו ואין מצווה על ממונו. ועל ראית רב אלחנן ראיתי שרצה אחד לתרץ ששם המציל הוי האב ולא הגרושה, והאב שהוא המציל חייב לשכור את גרושתו להציל (כדנלמד בסנהדרין ע"ג א' באל תעמוד על דם ריעך) ולכן אה"נ האב עושה בחינם. ועוד יש לפלפל בזה שלי נראה (וראיתי אחד שר"ל בדומה) שאין מצוות גמ"ח חיובית בדבר שהוא תמידי, דהיינו שגמ"ח רק מחייב לעזור למישהו באופן מיוחד המזדמן לפרקים, אך אין חיוב לגמ"ח בכל דבר שהוא ממנהג העולם לשכור פועל לכגון דא, דאל"כ לא שבקת חיי לכל בריה וכל אחד יצתרך לעזור לבעה"ב בכל צרכיו מדין מצווה, ולכן קושית הרב אלחנן ממניקה לא קשה מידי, ששם היא ממש כעין פועלת שנשכרת להניק לזמן מרובה ואינה מחוייבת בלי שכר, ויסוד זה גם יבאר מדוע ספן יכול לקחת שכרו ומדוע מלמד יכול לקחת שכרו וכדומה.
ולהנ"ל נראה לי לבאר הר"ן בסוגיא דילן בביקור חולים. דמקשים העולם על הר"ן שאומר שביקור חולים בישיבה הוי מצוה רק בחינם אך בשכר לא הוי מצווה ותמוה ממ"נ האם זה מצווה או לא. ונ"ל שלדעת אם ישיבה זה מצווה תלוי אם מנהג העולם לישיב אצל החולה באופן שזה בגדר דבר המזדמן ומתחייב במצות ביקור חולים, או שזהו פעולה שנעשית ע"י פועלים ולא נכלל בגמ"ח של ביקור חולים. והר"ן סובר שזהו דבר גבולי ו ולכן תלוי במנהג המקום, דמקום שעושים בחינם נעשה מנהג המקום שנכלל במצוות ביקור חולים אך במקום שלוקחים שכר כבר הוי עבודת פועל ולא הוי מצוה.
וודאי שמצוה קצת הוי, שכל פועל ואפילו בעל מאפיה אם כוונתו לשם שמים לעזור לבני אדם מצוה מקיים כדאיתא בבעלי המוסר, אך לענין ההלכה לא נחשב למצוה לעניינים של לקחת שכר ולהנאה בנדר, שכיון שסוף כל סוף לוקח שכר עושה להנאתו ג"כ, כנ"ל בס"ד

Nedarim 39a - Mudar hana'ah visiting the sick

The gemara trying to figure out the case of the mishna says that in a case where the property of the sick person is off limits to the visitor, it should be assur for the visitor to come because the "drisas haregel", meaning being in the home of the madir is receiving benefit from him. Although R' Elazar is the opinion who holds that drisas haregel is assur, but the chachamim argue; the Ran wrote on 33a in the name of the Ramban that the dispute between R' Elazar and chachamim is only about walking through the yard, but to stay in his chatzer (and certainly home) would be assur according to everyone.

The Ran then asks, why don't we say that since the visitor is doing a mitzvah, the benefit should be memeila and it should be permitted to visit even though the visitor will receive a benefit? The Ran answers "ומשום מצוה לית ליה לאתהנויי מאיסורא". Meaning, the sevara of doing a mitzvah and the hana'ah being memeila (like we say by teaching torah, supporting his kids...) does not take away the aspect of hana'ah, rather since the madir is focusing on his mitzvah it is not considered as if "HE" is providing the benefit to the mudar. But, in this case the mudar himself is doing the mitzvah and receiving the benefit of being in the madir's house, so the mitzvah is not matir. The only possible sevara for the mitzvah to be matir in this case is to say mitzvos lav leihanos nitnu would even be matir the physical benefit of being in his house. However, the Ran goes lishtaso in rejecting the Rashba 15b that mitzvos lav leihanos nitnu is not matir hana'as haguf.

Nedarim 37a - More on teaching Torah to a mudar

The Ran says that for teaching torah to the mudar, it is permitted to teach torah shebal peh because there is no $ value, and as far as the teaching of torah itself we say mitzvos la'v liehanos nitnu (as i spoke about in the previous post). However, the Ran permits charging s'char batala for torah shbal peh ans proves it from a yerushalmi. Someone in my shiur asked me that it should be assur to teach even torah shbal peh in a situation where there is s'char batala that he can charge for? I answered that if the Torah itself has a $ value for the tutoring then there is a direct benefit being provided from madir to mudar and is assur. But, if the only payment that the madir should be receiving is s'char batala, this does not give a value to the torah itself, rather it is like the madir is suffering a loss or damage by teaching. He is allowed to receive reimbursement for the loss he is suffering but would not be forbidden by a mudar ha'nah since it still doesn't place any value on the torah being taught.

However, after thinking about it more the mishna says that by returning a lost object if the looser normally pays the machzir, then it would be assur by a mudar (unless he give the money to hekdesh). But there also it is only s'char batala that he is allowed to take, nevertheless it would be considered benefit to the mudar to return it for free. Here too we should consider the torah taught for free without paying for s'char batala to be a benefit? Perhaps the only case that it is permitted to teach is when the teacher has no other job and there is no s'char batala applicable.

Also, the Yerushalmi quoted by the Ran implies that Targum goes hand in hand with mikrah in that one may charge. Does this contradict the gemara on 37b that says Targum is a halacha l'moshe misinai and one cannot charge? It seems to be a machlokes by targum just like there is a machlokes by pisuk ta'amim whether one can charge.

Nedarim 35b - Teaching Torah to Mudar Hana'ah

The Ran writes that one is allowed to teach torah shebal peh to a mudar hana'ah. The fact that it is Torah shebal peh ensures that there is no dollar value to the teaching since one is not allowed to charge for teaching torah shebal peh. But, the Ran is still apparently bothered that even if there is no dollar value, it should still be considered a hana'ah and therefore offers the solution of "mitzvos la'av leihanos nitnu". The concept seems a bit odd when applied to this situation. Usually Reuven is not allowed to receive a particular benefit from an object if it is assur bhana'ah, yet if the benefit is a mitzvah for him we allow him to do it. Here, the mudar is receiving the benefit and we allow him to receive this benefit since there is a mitzvah on the madir to teach torah. Unless the Ran means that the mitzvah on the mudar to study torah entitles him to learn from the madir and receive that benefit.

R' Akiva Eiger points to a Turei Even who questions how will the opinion who says that mitzvos are leihanos nitnu, going to explain the heter to teach torah to the mudar? The Imrei Baruch answers based on the Rambam (who says like the nimukei yosef that i quoted yesterday) that just as one who returns a lost object is not considered to be benefiting the owner since he is "employed" by G-d. So too one who teaches Torah to a mudar is working for G-d, so it is as if G-d is providing benefit to the mudar, not the madir. This would indicate that the Ran does not hold of this sevara from the fact that he needs to say mitzvos la'av leihanos nitnu.

הנאה בנדר לעומת הנאה בדיני יורד לשדה חבירו

בענין פורע חוב חבירו במודר הנאה הגמרא תולה במ"ח חנן וחכמים, דהיינו דלחכמים שהלווה חייב לשלם לזה שפרע חובו נחשב הנאה ולחנן שפטור הלווה א"כ לא ממש נהנה
ובמחזיר אבידה רגיל, וודאי שא"א לחייב את בעל האבידה לשלם למחזיר, חוץ משכר בטלה, דהיינו שבמחזיר אבידה בין לחנן ובין לחכמים לא נחשב מהנהו בדיני ממונות של מהנה חבירו
וא"כ לכאורה קשה, דלמ"ד אחד בלישנא בתרא אסור להחזיר אבידה כאשר נכסי מחזיר אסורים על בעל האבידה, דהוא מחשיב את חזרת האבידה להנאה של בעל האבידה מהמחזיר, א"כ לכאורה היה צריך להיות שק"ו בן בנו של ק"ו שיהיה אסור לפרוע לו חובו ששם הרי יש מ"ח בין חנן וחכמים אי נחשב מהנהו אף בדיני ממונות
מה שמוכח מכאן שבנדרים הגדר של מהנהו הוא שונה מגדר של דיני ממונות של מהנה נכסי חבירו, שהכא תלוי אי נותן באופן פיזי דבר לידי המודר. ובדומה לזה עיין בתוספות שמקשה שלכאורה פרוטה דרב יוסף לא צריך שיחשב הנאה דהרי זה דומה למבריח ארי - וע"ש בתירוצו

Nedarim 33b - Revisiting returning a lost object for mudar ha'naah

i posted about this issue in kesubos and questioned why it was mutar for reuven to search and invest energy into returning shimon's lost object. Shouldn't the tircha be a violation of providing him with benefit (even if the actual object is mutar to return since it belongs to shimon anyway)?

http://hearos.blogspot.com/search?q=lost+object

I found that the Nimukei Yosef addresses this question directly:

כתב הנמוק"י בנדרים יא: בדפי הרי"ף וז"ל ואי משום מאי דטרח האי במאי דאהדרה, לנפשיה עביד משום מצוה דיליה ושליחא ואגירא דרחמנא הוא, והרי הוא כאילו פרעו אחד מן השוק כדי שיחזיר לזה שהוא מותר עכ"ל

The Nimukei Yosef says that since his primary goal is to perform a mitzvah "he is being paid by G-d" and therefore not considered to be benefiting shimon through his efforts.

Nedarim 33b - Mavriach Ari

We already discussed this somewhat in kesubos 107 http://hearos.blogspot.com/search?q=mavriach but there is more to talk about.

The Ran assumes that we need the sevara of mavriach ari for all 3 cases listed in the mishna. The gemara discusses paying a debt for someone who is assur to receive hana'ah from you. The heter is either based on the opinion of Chanan who says that when reuven pays shimon's debt on the condition that shimon will owe him money, shimon does not owe money to reuven since he never requested the loan, therefore when he does it on the condition of mechila it is not considered benefiting shimon - that is called mavriach ari, meaning he simply prevents shimon from suffering a loss. The other possibility is that we are speaking about a case where shimon doesn't actually owe anything since he stipulated with the lender not to collect, so when reuven pays the "debt" for him, shimon is not receiving any real gain.

The Ran understands that by being paying his shekel we can also use the concept of mavriach ari according to Chanan. However, it is slightly more complicated because aside from the concern of getting the gizbar (who is like the lender) off shimon's back, reuven is buying shimon a share in korbanos. Therefore the Ran has to say that even if shimon does not pay, he is still entitled to a share in the korbanos (as rashi writes in kesubos, not like tosafos there).

Being that the Ran holds that mavriach ari applies to the paying the shekel as well, he must hold that mavriach ari applies even to a situation where the damage is definite. This is to the exclusion of Tosafos who writes that mavriach ari only applies when reuven saves shimon from the fear of a lion but not from an actual lion. Tosafos holds that if the damage is definite then reuven cannot protect shimon from it, since it qualifies as providing him benefit. Tosafos can only say this because they understand the case of paying the shekel is speaking according to everyone where shimon already payed and it was lost, but if shimon has not yet payed then reuven cannot pay for him because shimon has no way out of the situation, it is a definite loss and therefore is not called mavriach ari. The Ran clearly disagrees with Tosafos and holds that even when the damage is definite such as paying his shekel that was never payed for, we can apply mavriach ari.

It is not so clear how the Ran will answer Tosafos question from the case in Baba Metzia where a shepherd saves the herd from a lion attack and we require the owner to pay the shepherd and do not consider it mavriach ari. Why would we consider the case of paying the shekel to be mavriach ari? See first answer of Tosafos B.M. 31b for a possible answer, but it needs explanation.

bris

The following concept can explain the אגדתא in Daf 32.

A bris on the body says that the physical world alone is not complete, only in as much as we attach to the world of spirit do we become whole. The gemara elsewhere explains that G-d created man incomplete and told him he must complete himself by performing a bris. So we have both sides of the coin. G-d says to his people that he needs us to complete the world and we tell G-d that the continuity of our people is in His hands.
וזהו ענין כריתת ברית, שהגר"א מקשה והרי כריתה זה ההיפיך מחיבור ומדוע קוראים לברית המחברת שני הצדדים בלשון כריתת ברית - אלא ללמדך שברית אמיתי אומרת שכל צד כורת את עצם חיותו ונותן לצד השני באומרו שכל חיותו תלויה בשני. וכן בברית בינינו ובין ה' - הוא נותן לנו תורתו ואנו נותנים לו את המשך קיומינו
sorry, thought i would have time to finish this, but it didn't come to pass...

Nedarim 32a - Sakana prior to Matan Torah

The maharsha raises a question how was moshe allowed to miss the mitzvah of milah out of concern that it would be dangerous for the child, since the heter to forgo a mitzvah due to pikuach nefesh was introduced with "v'chai bahem" at matan torah? The maharsha explains that actually it is a sevara that one does not have to give up their life for mitzvos (perhaps the sevara is based on r' shimon ben minasya in yoma "better to violate one shabbos so that you can keep many shabbasos", meaning it is better to violate a mitzvah now so that there will ultimately be a net gain in the performance of mitzvos). However, when the Torah was given and introduced the idea that for rotzeach and na'arah ha'miurasa one must give up their life, we needed a heter of "v'chai bahem" so that we don't learn all mitzvos from those. Based on this approach, the heter of v'chai bahem is applicable to b'nei noach as well, meaning that they are not required to give up their lives to keep the 7 mitzvos (but if they would violate without an o'nes they receive capital punishment). R' Akiva Eiger (Y.D. 62) quotes the Pri Megadim (in his sefer on chumash "teivas gomeh") who discusses whether a jew is allowed to give eiver min ha'chai to a goy when he needs it for pikuach nefesh - if he is allowed to eat it for pikuach nefesh it is not lifnei iver for a jew to give it to him, but if he is not allowed to eat it, it would be lifnei iver for a jew to pass it to him.

This is also connected to Rashi in Pesachim 53b that chananya mishael v'azraya were willing to give up their lives and didnt' rely on the drasha of v'chai bahem, because they learned a kal v'chomer from the frogs. The maharsha asks, how can they learn a kal v'chomer from frogs, the frogs were not commanded in v'chai bahem therefore they were allowed to give their lives for kiddush hashem, but chananya mishael v'azraya who were commanded in v'chai bahem, even though they were also commanded in kiddush hashem, should not give their lives. Now, if the maharsha by us is correct that there is a sevara even w/o v'chai bahem not to give up your life for a mitzvah, then the distinction of v'chai bahem should not make any difference since all v'chai bahem does is return you to the same status that you would be without a limud from rotziach and na'arah (which obviously the frogs don't have).

Nedarim 30b - Wearing Yarmulkas

The Shulchan Aruch mentions both in o.c. 2:6 and 8:2 the idea of men covering their heads. The Magen Avrohom quoting Bach writes that one cannot walk 5 amos without covering their head, and even less than 4 amos is a midas chassidus not to go without a head covering. The Machtzis Hashekel points out that it cannot be that 4 amos is assur m'ikar hadin and less than 4 amos is midas chassidus because the Magen Avrohom writes elsewhere (91:3) that even 4 amos is only midas chassidus. Therefore, the entire idea of a head covering (for a man) must be midas chassidus, just that the bach mentioned by magen avrohom says that even less than 4 amos would be a midas chassidus which is against the pashtus of the shulchan Aruch. The GR"A in siman 8 elaborates and similarly concludes that "the rule is, there is no issur at all to go with an uncovered head, unless one is going in front of gedolim or davening then it is proper m'tzad mussar, and the same for the rest of the day for kedoshim who are standing before G-d constantly". However, the Taz 8:3 in quoting says hat nowadays there is an issur gamur to go without a head covering because of chukas ha'akum. R' Moshe (o.c. 1:1) discusses a comment made by R' Shlomo Kluger who seem to say to walk more than 4 amos one must cover their entire head (which R' moshe interprets to mean the majority of his head) and less than 4 amos must cover part of their head. R' Moshe concludes that one who wants to be machmir forRS"K should wear a large yarmulke, but m'ikar hadin one is not required to do so since even according to him the issue of covering the entire head is only midas chassidus, since the chukas ha'akum iss of the taz is certainly accomlished with even a small yarmulke.
Clearly even in the time of the gemara men were apparently covering their heads sometimes. Tosafos comments that men "are allowed to uncover their heads on a temporary basis even in front of the world, but women may not". Tosafos implies that it is more than a midas chassidus to wear a yarmulke, it is an absolute obligation, but the obigation is only to walk around regularly without a yarmulke. If one would take off a Yarlmulke temporarily for a business meeting, Tosafos would say that it is completely mutar.

נדרים ל' הנותן לאשה שתי פרוטות

נ"ל שהנידון בגמרא בשאלת רב אושעיא בנותן שתי פרוטות לאשה וכו' הוא בתרתי: א' מצד החפצא של האשה ל"ש מעשה קידושין שני במי שכעת כבר מקודשת, ב' מצד הגברא שמקדש שהוא לא בעלים לעשות מעשה קנין באשה אחר שמתגרשת. והדברים יובנו לפי מהלך הסוגיא, כדלהלן
לכן הגמרא מנסה להביא ראיה מבר פדא ומדחה, והביאור דאה"נ מצד חפצא של הדבר זה דומה, שכמו שייך מעשה הקדש בדבר שכבר מקודש אך אין ראיה לחידוש השני שמצד הגברא זה שונה, שהכא בהקדש כשיוצא מרשות הקדש נכנס מיד לרשות הבעלים ולכן הוא בעלים לעשות מעשה הקדש (ואף בשעה שהוי הקדש שייך קצת לבעלים דומיא דקרבן דנחשב של הבעלים) משא"כ באשה אחר הגירושין יצא מרשות בעל (והיא לא בעלים על מעשה הקידושין - כמבואר בר"ן). ולכן אין ראיה לחידוש השני. ואח"כ הראשונים שהר"ן מביא שפושטים בעית ר' אושעיא מההיא דר' אילא סוברים שמשם שפיר יש ראיה שאף שחסר בבעלות של זה שעושה מעשה ההקדש כיון שזה יוצא לרשות של הקונה, עדיין שייך למוכר לעשות מעשה הקדשה וא"כ כן אפשר להוכיח את החידוש השני ושפיר אפשר לפשוט דין ר' אושעיא. והר"ן שחולק ס"ל שכדי לפשוט דין רב אושעיא צריך למצוא דין בגמרא שיש לו שתי הדינים ביחד, א' שכבר מוקדש והחפצא מופקע מעוד הקדשה, ועוד צריך ראיה שהבעלים שייכים לעשות מעשה הקדשה אף שחסר לו בבעלות. והבן
לא באתי כאן בקושיות ותירוצים אלא להבין השקלא וטריא בגמרא ובר"ן אשר קשה להבינם

Nedarim 29b - 30a - Kedusha Returning Automatically

Bar Pada says that the kedusha that was placed on the trees is a constant status of kedusha so that even if it removed through redemption (before the trees were cut), the kedusha returns automatically. The gemara wants to deduce from here that if a man would be mekadesh a woman with 2 coins saying that if they get divorced the second coin should automatically create a new kiddushin that it would work (the gemara then goes on to make distinctions between the redemption by the person himself or a third party getting involved, and the woman returning to her own reshus through a divorce is like a third party as explained by the famous Ran).

Why is the gemara able to prove anything from Bar Pada - we don't pasken like Bar Pada, rather like Ulah, so even if we can prove this from Bar Pada it is irrelevant? According to the Rashba (cited in Ran 28b) that Ulah agrees with Bar Pada about this point that the kedusha will always come back after redemption, and they only argue about the case where the trees were cut, it works out well since on this point Ulah agrees. But according to Ramak (quoted in Ran) that Ulah disagrees with the first point as well because he holds that the language of "until they are cut" is meant to automatically remove the hekdesh when they are cut, but not meant to indicate the hekdesh should automatically come back after the redemption while they are still standing. So, why are we proving from Bar Pada that the second kiddushin would occur after the divorce, rather than proving from Ulah that it will not?

It seems clear that even according to the Ramak, the concept of Bar Pada that kedusha that is removed by redemption can return automatically is definitely accepted by Ulah as well. The dispute between Ulah and Bar Pada is merely what the person meant by the language of "until they are cut". But if he stated explicitly that he is makdish from now until it is cut and even if redeemed should become hekdesh automatically, all agree that it would work. Therefore, this concept the gemara is learning from is universally accepted and if the proof would work, it would reflect on the halacha l'ma'aseh even though we pasken like Ulah.

Nedarim 28a - Dina d'malchusa Dina

I am not sure whether to write this in english or hebrew, i will opt for hebrew and if there are any preferences please comment so that i will know for next time. It is a longer than usual post, but i think a very fundamental one.

במשנה משמע שמוכסין לוקחין המכס שלא כדין ומש"ה מותר לנדור לשקר, וקפריך ממימרא דשמואל (שהוא מקובל ולית מאן דפליג עליה כמש"כ הריטב"א) דדינא דמלכותא דינא? ומשני א. במוכס שאין לו קצבה (ובזה הביא הרא"ש ב' פירושים: לפירוש הראשון כיון שהוא מרבה לזה וממעט לזה ואינו שוה לכל בני המדינא לאו דינא הוא אלא חמסנותא, ולפירוש השני כיון שאין לו קצבה מרבה ליקח יותר ממה שהמלך חפץ. מ"מ כתב הרא"ש דאף לפירוש השני כולו גזל, ולא רק מה שלוקח יותר ממה שצוה המלך. מ"מ הנפק"מ בין הפירושים במכס שאינו שוה לכל בני המדינה, דלפירוש ראשון חמסנותא הוא, ולפירוש שני דינא הוא. אכן, מסתברא דזה דוקא כשמרבה וממעט כפי רצונו אבל אם מרבה המכס לעשירים וממעט לעניים, ודאי דינא הוא). ב. מוכס העומד מאליו שלא במצות המלך והוא ממש חמסן. ואפשר דזה אמר חדא וזה אמר חדא ולא פליגי, דבמוכס העומד מאליו הוי חמסנותא אע"פ ששוה לכל בני המדינה, ובמוכס שאין לו קצבה הוי חמסנותא אע"פ שעומד במצות המלך. וזה מפורש ברש"י בב"ק קיג. דמוכס העומד מאליו אע"פ שיש לו קצבה הוי חמסן ולא דינא הוא

והנה, בגמ' דידן יש רק ב' תירוצים לפרכת הש"ס דדינא דמלכותא דינא, אבל בב"ק קיג. קאמר רב אשי במוכס כנעני ופרש"י שם לפי מה דמסיק בגמ' דהפקעת הלואתו מותר, דמותר להבריח המכס ממלך עכו"ם משום דהוי הפקעת הלואתו. וזה קשה בין לדעת הרמב"ם שסובר דשייך דינא דמלכותא בין במלך ישראל בין במלך עכו"ם כדמפורש בדבריו (פ"ה הל' גזילה הל' י"א) וגם בפיהמ"ש. וגם קשה לדעת הר"ן אצלנו דדינא דמלכותא שייך דוקא במלך עכו"ם מפני שהארץ שלו (באמת נראה שעיקר החילוק אין בין ישראל לעכו"ם, אלא דמלך עכו"ם מסתמא הוא בחו"ל, ומלך ישראל מסתמא בא"י). מ"מ בין להר"ן בין להרמב"ם משמע דבמלך עכו"ם מיהא אמרינן דינא דמלכותא דינא? ודחק הכס"מ ליישב הגמ' לפי דעתם, דדוקא משום סכנת נפשות אסור להבריח, ולפי"ז יוצא קולא גדולה דבמלך עכו"ם כשאין שם חשש סכנת נפשות מותר להבריח המכס אף בחו"ל. אמנם במשל"מ דוחה דברי הכס"מ שמדברי הרמב"ם לא משמע כלל דטעמא דאסור להבריח המכס במלך עכו"ם הוא משום סכנת נפשות. אלא שסובר הרמב"ם דרב אשי דמוקי ליה במוכס עכו"ם כוונתו כשהמוכס עכו"ם קנה המכס מאת המלך, דאף כשיש לו קצבה והוא קנה המכס מהמלך מותר להבריח דהוי הפקעת הלואתו, אבל כשלא מכר המלך את המכס אלא הוא מינה אפוטרופוס לגבות בשבילו "אין כאן עסק להפקעת העכו"ם שהתירו בגמ' כיון דדינא דמלכותא דינא, והרי גזר שלא יבריחו המכס, ודאי המבריח גוזל הוא וזה ברור". הרי סובר המשל"מ דבמדינתו אסור להבריח המכס כדמשמע מהרמב"ם

עיין במשנה למלך שם שהביא לשון הר"ן שלא נמצא לפנינו שכתב אהא דלא הוי נדרי אונסין כשמכר המלך הקנס לישראל, דכיון דדינא דמלכותא דינא לאו אונס הוא וכתב ע"ז "מיהו אין ממונה זה רשאי להכריח לישראל חבירו לפרוע לו את המכס, אם לא מיראת המלכות, דנהי דדינא דמלכותא דינא, לא יהא אלא הלואתו הא קיי"ל דהפקעת הלואתו שרי ע"כ. הרי משמע שאסור להבריח המכס כשישראל חבירו קנה רשות לגבות המכס דבישראל אין להתיר הפקעת הלואתו (כדמפרש המשל"מ בסוף דבריו), אבל כשהוא רק ממונה לגבות המלך בשביל המלך מותר לישראל להבריח המכס משום דהוי רק הפקעת הלואתו, ואע"ג דדינא דמלכותא היינו רק שמטעם זה לא הוי נדרי אונסין דלא אונס הוא, מ"מ כשאפשר לו להבריח ממנו מותר לעשות כן. כן נראה מדברי הר"ן הובא במשנה למלך, ודלא כהרמב"ם דאסור להבריח משום דינא דמלכותא דינא. וזה מדוייק בלשון הר"ן בדברי הר"ן שלפנינו אף שלא נדפס סוף דבריו לפנינו, שהרי כתב הר"ן דאם קנה אחד המכס (דהיינו ישראל) חייבים ליתן לו, אבל כשלא קנה והוא ממונה מאת המלך לא כתב הר"ן שחייב ליתן לו, אלא כתב "דליכא אונסא כיון דדינא דמלכותא דינא", והוא מדוייק היטב לפנינו

Nedarim 27a - Nidrei Onsin

1. In the case where a person makes a stipulation with the beis din that his zechuyos should be lost if he does not show in 30 days, and fails to show up due to an o'nes, his zechuyos would be batul. The gemara questions that his zechuyos should not be batul for two reasons: 1. o'nes rachmana patrei - just as the girl who commits adultery b'ones does not qualify as committing adultery, so too the person who fails to show in court due to an o'nes does not qualify as "not showing". 2. Similar to Nedarim - his original stipulation was that if he DECIDES not to show, he should loose his zechuyos, but if an o'nes prevents him from showing then he does not loose zechuyos.

2. The Ran clearly indicates that the first approach would only work by a real o'nes that would actually prevent him from showing, but the second approach would work even by a partial o'nes, such as his son getting ill where it is difficult for him to show but not impossible.

The gemara challenges whether we can learn from na'arah ha'meurasa to other cases because "maybe regarding killing her is different". The Rosh offers 2 approaches in this distinction (see rashash for a slight yet compelling change of girsa in the Rosh). 1. we always do whatever possible to avoid capital punishment so we are more likely to use o'nes as an exemption from capital punishment than from other things ("rashi" seems to say this as well). 2. when one could have stipulated and failed to do so, we assume he included even a case of o'nes but by the adultery where she could not have stipulated on anything, the o'nes is an exemption.

3. The Ran and Rosh argue about R' Huna's logic to make a distinction between the person stipulating to be mevatel his zechuyos and the case of nidrei o'nsin. Ran says in the case of neder where the inviter is making the neder that effects the invitee, he doesn't care enough to be expected to stipulate, but when one makes a condition about themselves they are expected to stipulate. The Rosh says that the default by money matters is not to follow what he is thinking (such as the exclusion of o'nes) unless he explicitly stipulates, but by neder we follow what he his thinking if we are sure that he didn't mean to include a case of o'nes. The Keren Orah explains that the Ran and Rosh go lishatasam on 24a. They argue who is making the neder in the case of the mishna: Ran holds that the ba'al habayis is making the neder, therefore he can say that he doesn't care enough to stipulate since he is not affected by the neder. The Rosh holds that the invitee is making the neder and therefore cannot say like the sevara of the Ran since he should care enough to stipulate, therefore he has to come up with another difference between the 2 cases.

דין דעת בנדרים

R' Avi, I know this might belong as a comment... Because if its importance I am posting anew, but the editor has the last word...
(update: now that i see how long it got, i will post as comment)

Nedarim 25a - 613 Mitzvos

The gemara seems to assume that accepting a shavua to keep the 613 mitzvos is exactly the same as accepting a shavua to keep the entire Torah. Is this really true? First, the Ramban at the beginning of sefer hamitzvos discusses the possibility that the #613 is a PR stunt but not necessarily accepted by all sources. Even if we are to assume that our gemara buys into the 613 idea as do all the Rishonim who list the mitzvos, aren't there still other "mitzvos" in the Torah that are not counted in the 613. There are many mitzvah concepts that would qualify as "ratzon ha'torah", even if not an absolute obligation, and by only accepting the 613 mitzvos we would seemingly not be accepting all the thousands of other points that the Torah want us to accept! How can 613 be the same as a shavua on the entire Torah?

nedarim the 3rd perek

The Perek deals with 4 Nedarim that don't need an official annulment rather they are self nullified. This law is learned from the דרשא of האדם בשבועה.
Things that need to be clarified:
1- why do we need a special Pasuk by Nedarim/Shvuos that if one doesn't have proper דעת the Neder is בטל? Why is it different then מקח וממכר and the like.
2- Careful Iyun in the Perek must be done to see if we do follow regular laws if ביטול מקח and אונס in Nedarim. note that we don't have a Perek of 4... in Gitin or Bava Metzia!!!
3- Are the levels of אומדנא the same here then in other places in order to take something out of דברים שבלב.
All these inquiries are really one in essence. I myself still don't have this clear. On simplest level it would seem that even אונס which is not enough for other places in Shas is enough in Nedarim because of the new Drasha. Beware that the Bircas Shmuel in Nedarim 14-15 deals with these issues in his unique way. ולא באתי אלא לפתוח פתח

Nedarim 23 - 24 - A few points:

1. Regarding being oleh regel - the gemara seems to imply that there is a concept called "oleh regel" even post churban. The maharatz chiyus discusses this and suggests that people at least went to daven or perhaps even to bring korbanos. However, the Rosh says very beautifully that they came to study Torah "and even women were noheg a mitzvah to come there and see the kavod ha'torah". It must of been similar to the daf yomi siyum in MSG.

2. Kol Nidrei - The Rishonim seem to understand that the minhag of kol nidrei is sourced in this gemara (Tosafos) and the purpose cannot be for past nedarim for many reasons, rather the purpose is to make a stipulation on future nedarim of the upcoming year that they should be binding. Some Rishonim (Rabbeinu yacov Tam in Ran and Tosafos) recommends changing the text to clearly indicate that the purpose is for future nedarim. However, the Ran seems to hold based on the gemara that we don't want to publicize this concept that you can stipulate in advance to remove any future nedarim (provided that at the time of the neder you don't remember about it). Therefore, the text was specifically written with ambiguity as if it were referring to past nedarim, when in fact it is referring to future nedarim so that the amei ha'aretz would not realize that there is such a concept.

3. K'ilu Hiskabalti - The Ran says that this concept works only by an active condition to make it as if it were done, but does not work by a passive condition to make it as if it were not done. The Ran clearly indicates that this does not only work by a gift where it can be taken and returned, but also works for example if one would say something should be assur "if you do not go to a particular place", the madir can say that even if you did not go i accept it as if you went. But if one would say something should be assur "if you go to a particular place", the madir cannot say that even if you didn't go i consider it as if you went (the Ran brings others that permit even this case because it is all dependent on the will of the madir). What is really the difference? I understand by a gift that can be taken and returned, it makes sense to say "afukei matarasa lama li", but when the condition is not to receive something but rather an action that the mudar must make, how can we consider it as if he went when he actually did not go?

4. Ran on 14b indicates that there is no issur in neder shav (rosh argues). Ran on 24b indicates that there is no malkus but implies slightly that there is an issur. Ran on 25a says clearly again that there is no issur (at least in comparison to shavua).

Nedarim 22a - A Few quick points

1. Making a neder is building a bama - Ran explains that doing something that "feels like" a mitzvah is not necessarily a mitzvah, unless we were commanded to do it. See Beis Halevi that after the sin of the eigel, the Torah in Parshas vayakhel stresses that everything was done "as G-d commanded". The Meshech Chochma (beginning of vayikra) explains that bamos were a heter to use as an outlet for avoda zara, but not really lichatchila (like Rambam's understanding of Korbanos). Similarly one who makes a neder is trying to set a geder from an issur, but is doing an issur by adding to the Torah's list of issurim.

2. In the story where one Jew murdered another and Ulah gave him a shkoyach and then advised that he open the cut to make him die quicker - R' Yochanan says that ulah's heter was pikuach nefesh. The Rosh implies that Ulah had 2 intentions: 1. to save his life. 2. make the person die quicker (less painful). However, he was concerned that he was machzik y'dei ovrei aveirah, and to that R' Yochanan responded that for pikuach nefesh it is not a concern. It is not so clear if pikuach nefesh was necessary for Ulah's heter for expediting the person's death which is tantamount to murder. BUT, even if we assume that it was pikuach nefesh, this gemara indicates that although one cannot murder (or presumably say something that will cause murder) to save his life, that is because "who says his blood is redder". However, here where Ulah was a Chayei Olam against the victim who was a Chayei Sha'ah, we apparently are able to choose and give preference to Chayei Olam. This is really based on the Chazon Ish (Y.D. 69:2) understanding of the story with ben peturah and r' akiva [Another possibility, although a much bigger chiddush, is that even without pikuach nefesh, one may not actively b'yadayim expedite the death of another jew even to save him pain, but may advise that it be done - but let me be clear that I don't think that this is true].

3. The Ran implies that the issue of being matir a shavua that was made using the name of Hashem is not that retroactively it will turn into saying shem shamayim l'vatala, rather it is just that a shavua with the name of Hashem is very chamur and one should not be matir it. The reason that it wouldn't be shem shamayim l'vatala is because we look at the status at the time when he said it, at which point it wasn't l'vatala. This would be consistent with the Ritvah 18a that if at the time it was said it was shavuas shav, it cannot be fixed by being matir a preexisting shavua to allow this one to be chal - we always follow the status at the time that he said it and don't retroactively take it away from beign l'shav, or make it into l'shav.

עבר הירדן

(the following is based on research done by a dear friend and mentor, who complied this from various achronim including: משנת רב אהרון, ר' דוד קרלינר, ר' מנחם זמבה, הגרי"ד סאלווצייק, משך חכמה and others)
the ran comments that one may not bring the Omer from עבר הירדן. (there is a rashi somewhere in Sanhedrin that argues) What you see from the Ran is that the Kedusha of עבר הירדן is different then that of the rest of Eretz Yiroel. The achronim explain that the land of עבר הירדן wasn't promised to our for-fathers, rather was captured by Moshe as כיבוש רבים, this gives it Kedusha of Eretz Yisroel but on a lower level.
You might ask, if עבר הירדן has a status of כיבוש רבים then why doesn't have the same issues of סוריא that, according to some rishonim, is problematic because it was captured by Dovid before the rest of Eretz Yisroel was completely conquered? answer: that here Moshe had no choice in conquering Sichon and Og, because they wouldn't let them pass, therefor it is better then סוריא
Interestingly, the achronim say that there is another נפקא מינא - like this: The "mainland" of Eretz Yisroel doesn't require כיבוש to give it its Kedusha, this is why for חלה all that is needed is that you fulfill the תנאי of "most people coming into Eretz Yisroel", but you don't need כיבוש, and once the Jews came in the land they were obliged in the Mitzvah of Challah. Other mitzvos, however, need also כיבוש for them to take effect. so we have in mainland Eretz Yisroel itself 2 levels of Kedusha, one that is G-d given and one that requires our כיבוש
interesting to note that in the Mishna in Kelim where it lists the 10 קדושות of Eretz Yisroel, עבר הירדן is not listed, because that mishna deals only with the other type of Kedusha, that of "mainland" Eretz Yisroel with its source - the בית המקדש.
Lastly, on a מחשבה note you see that Eretz Yisroel is a place where the Kedusha (at least parts of it) is predicated on 2 factors, G-d's promise thru prophecy and OUR input in כיבוש. The idea being that the land is the place where we join G-d in "finishing off the work needed to be done" (reference Rebi Akiva on Milah). if we are to G-d as a bride is to a groom, the land is our house where we practice our covenant of marriage.
I have my own thoughts why, based on the above, the Omer cannot be brought from עבר הירדן, but we'll leave that for now...

Nedarim 21b - Pesach and Charata

One of the yesodos of hataras nedarim is the two way in which the neder can be removed: pesach or charata. The Ran defines the terms: "Pesach" - A situation that if he realized at the time he made the neder, he would never have made the neder to begin with. The method of "pesach" manages to turn the neder into a neder ta'os as if it were made based on a false premise. "Charata" - Although there is nothing that would have stopped him from making the neder originally, he now realizes that the neder was made without proper yishuv ha'da'as i.e. out of anger and he really never meant it. This is called "Charata d'meikara". There is another type of charta which is called "charata d'hashta" that does not work according to anyone - when one regrets the neder from now on but does not regret it from its inception, rather he wants it to be removed from here on in. There is also a situation that is between "pesach" and "charata d'meikara" - when one says that if people would have appeased him originally then he would not have made the neder - this is not quite a "pesach" since he requires the intervention of others, but it is better than "charata" since there is something that would have stopped him from making the neder originally.

Based on the Ran's explanation that "pesach" renders the neder a mistake since its inception, it is not clear why you need a chacham to be matir it. Every person who realizes a situation that if realized originally would have detered him from making the neder, it should be null and void by itself without chacham intervention? The Maharit (1:19 quoting his father) and the R' Shlomo Eiger quoting the Mabit both say that m'doraysa when there is a "pesach" there is no need for a chacham, but the rabbanan didn't want a free for all and therefore insist that a neder only be removed by a chacham removing it. Based on this approach, the gemara on 9b that says that if one regrets the acceptance of nezirus it would turn his korban into chulin b'azara, works very well. Even though he does not go to a chacham to remove the neder, the very fact that a "pesach" exists renders the neder a ta'os and the korbanos will be chulin b'azara. However, the Ran who is madchik in that gemara that the existence of a "pesach" would not render the neder a ta'os without the process of a chacham being matir it, clearly rejects the notion of the Mabit and holds that even m'doraysa a chacham must be matir when there is a "pesach".

Nedarim 20a - מדת הבושה ועזות

בגמ' מבואר שמדת הבושה מעלה הן לישראל שמביאה לידי יראת חטא והוא סימן יפה באדם וכן מבואר ביבמות שמדת ישראל שהן ביישינין. וכבר העיר המהרש"א שזה לכאורה סותר הגמ' בביצה דקאמר מפני מה ניתנה תורה לישראל ומשני מפני שהן עזין, שהוא ממש להיפך ממידת הבושה. והעלה המהרש"א דבדרכי המדות הוא סימן יפה באדם שהוא ביישן אבל בדרכי הלימוד אמרו ולא הביישן למד וצריכים להיות עזין. ובזה מפרש הגמ' בביצה דקפריך מפני מה ניתנה תורה לישראל, מפני שהן עזין. זה יוצא לב' טעמים: א. שיכולים להצליח בתורה רק ע"י העזות מפני שאין הביישן לבד. ב. שהקב"ה החליט שהם צריכים התורה יותר מהכל כיון שבטבע הן עזין והם צריכים התורה כדי להתיש עזותן. ונראה שבזה נוכל להבין הא דקאמר בגמ' שבושה ניתנה לישראל במעמד הר סיני, ומי שאין לו בושת פנים בידוע שלא עמדו אבותיו על הר סיני. נמצא שבהר סיני בחר הקב"ה ליתן התורה לישראל מפני שהן עזין והם צריכים כח התורה כדי להתיש עזותן, וכשנתן להם התורה התורה מתשת עזותן ומכניס לתוכם מדת הבושה כדכתיב "לבעבור תהיה יראתו על פניכם" שזה כולל הבושה דרק ע"י בושה מגיעים ליראת חטא כנ"ל, ורק ע"י כח התורה שמתשת עזותן ומכניס להם מידת הבושה יכולים הם להצליח בתורתם, שאילולי הבושה לא יהיו מצליחים מפני שאין הביישן למד

nedarim 20 - living with opposite emotions

The Jewish soul is comfortable with opposite emotions. For example, Love of G-d vs Fear of G-d. How can you love and fear at the same time??? the Pasuk says וגילו ברעדה, which translates something like rejoice in fear, how do you do that??? but we do.
Any time you take an idea to its depth in Judaism you will find opposites. In our Daf alone you have it twice. 1st, you have the concept of needing to have shame as a sign for Fear of G-d. on the other hand, as the Maharsha points out, the Gemara in Beitza says that Jews are brazen and that is why we can accept the Torah.
והשני - בדין של "כפאו שד" מקורו מסוגיא דידן, עכ"ז בגוף הסוגיא למדנו שיש דין מספרת עם בעלה, דהיינו שלצורך מותר ומוצרך ועיין היטיב ברא"ש. ודי בזה
It is famous that in creation itself this paradox exist. G-d created a differentiated world that is One which in the world of philosophy makes no sense, if we are a part of G-d himself, how can we be we and He be He??? How about Predestination and Free-will. Is the world created with Kindness (חסד) or strict justice (דין).
The point being that in my humble opinion the Gemara teaches this concept in marriage because in depth this concept is in the essence of our relationship to G-d. Marriage, as we learn in Shir Hashirim, is the example in this world to our relationship to G-d.

Nedarim 19b - Safek Nazir Shaving

The Ran and Rosh both learn that the reason that a safeik nazir would not be able to shave his head to fulfill the mitzvah of giluach is that ideally the shaving can only be done after bringing the 3 korbanos: olah, shelamim and chatas (even though bidieved he is yotzei if he shaves after he brought just one korban), and since a safeik nazir can't bring a chatas because if he is not a nazir it would be chulin b'azara, he cannot even be megaleiach. Tosafos seems to say something much simpler that is not at all dependent on the korbanos. For a nazir to shave his head would be a violation of hakafas harosh (cutting his paiyos), and therefore m'safek he cannot fulfill the mitzvah of giluach.
I don't understand why the Ran and Rosh would not explain simply like Tosafos. The language of the gemara may lead them to understand that the problem with giluach is dependent on the korban, or it may be that they want to explain the gemara even according to those who hold hakafas kol harosh is NOT called hakafa. v'tzarich iyun.

Nedarim 18a - Neder on Shavua and Shavua on Neder

The Ran says that if one were to make a neder on top of a shavua, whether they had a shavua to eat a piece of meat or a shavua not to eat it, a neder would be binding since the shavua is just an issur gavra and leaves space for an issur cheftzah of neder to be chal on it. The Ran proves his point from the fact that one can make a neder on a d'var mitzvah. The Ran clearly understands that just as a mitzvas aseh is an obligation on the gavra, an issur la'av is also a prohibition on the gavra, so that one can make a neder to assur a piece of matzah (on pesach) and also to assur a piece of pork (like the ramban that i mentioned yesterday). Based on this the Ran very logically concludes that one can make a binding neder on a piece that he is pre-sworn on, whether he is pre-sworn to eat it or not to eat it.

Regarding making a shavua on top of a neder, the Ran is mechadesh that a shavua cannot be chal on a neder (Presumably since the shavua is not chal, it is tantamount to a shavua l'vatel or l'kayem a mitzvah that is not chal and therefore automatically a shavuas shav). He explains that when one makes a neder he is creating an issur cheftza on the object, and also an issur gavra on himself because the ba'al yachel is an issur gavra just as every lo ta'aseh in the Torah is an issur gavra. Therefore an neder includes both an issur cheftza and an issur gavra, so it does not leave any space for a shavua to be chal on it.

What would be if Reuven makes a neder to assur a piece of meat on shimon, can shimon make a shavua not to eat that piece of meat? According to the Ran 15a that there is an issur ba'al yachel on Shimon which is an issur gavra, then certainly Shimon's shavua won't be binding. But, according to the Rambam that the issur ba'al yachel is on Reuven, then maybe Shimon's shavua would be binding? But based on my assumption a few days ago that there would at least be an issur of lifnei iver in Shimon, that should also consitute an issur gavra and prevent the shavua from being binding.

Nedarim 16b - Shavua and Neder to be mevatel a Mitvah

The gemara says that one can make a neder to be a mitzvah since it doesn't directly go against the Torah obligation (Torah obligation is on the person and he is placing issur on the object), but one cannot make a shavua to violate a mitzvah since he going head on with a torah obligation. By shavua it makes no difference whether he is trying to make a shavua on an aseh (Shavua not to eat matza) or on a lo t'aseh (shavua not to eat pork) - the shavua will not be binding (unless it is made b'kollel in which case there is a lot of discussion in Rishonim). But by neder, it may only be binding if he makes a neder to be mevatel an aseh, but if he makes a neder on a lo ta'aseh (neder to assur pork), it is a big machlokes Rishonim (brought in Ran in shavuos and nimukei yosef here) whether such a neder is binding. The Ramban holds that it would be binding since the issur pork is an issur gavra and one can place on that an issur cheftzah. Perhaps those who argue with the Ramban would consider issurim such as pork to be both an issur gavra and an issur cheftzah so that both shavua and neder will not be chal on it.
Another issue is when one makes a shavua to be mevatel a d'rabonon mitzvah, is the shavua binding? The Shulchan Aruch in Hilchos Ta'anis (570) rules explicitly that the shavua would be binding since the mitzvah is only d'rabonon, a d'orayasa shavua can be chal on it and it would be forbidden to violate the d'oraysa shavua in order to perform the d'rabonon mitzvah (we saw in the Ran on 15b that even when a neder is binding d'rabonon and one has a d'oraysay mitzvah, he should forgo the d'oraysa mitzvah to maintain the d'rabonon neder since chazal are oker davar min hatorah b'shev v'al ta'aseh, certainly one must maintain a d'oraysa shavua and forgo on a d'rabonon mitzvah).

Nedarim 15a - Who is in violation of B'al Yachel?

The Ran understands that if Revuen makes his object assur on Shimon and Shimon then benefits from the object, Shimon is in violation of b'al yachel. The Rambam quoted in the Ran argues and says that Shimon is not in violation of b'al yachel since he is not the one who made the neder, rather Revuen is in violation of b'al yachel when shimon gets benefit. The Rambam seems to understand that the language of "b'al yachel divaro" implies that only the person who made the neder can be in violation of not keeping his own word, whereas the Ran understands that Shimon can violate b'al yachel for not keeping the word of Reuven. In other words, the Ran understands that when Reuven makes his object assur on Shimon it is tantamount to making it hekdesh albeit a lower scale that it only effects Shimon, so that Shimon will be in violation. But the Rambam understands that the issur placed on the object is purely a result of the madir keeping his word, therefore the madir would be the one in violation.

According to the Rambam, would it be assur for Shimon to benefit from Reuven's object? It would seem that the issur preventing Shimon from benefiting would be lifnei iver, meaning that through his benefit he is causing Reuven to stumble in the issur b'al yachel. Based on this, would it be mutar for Reuven to hand Shimon the object for Shimon to benefit from it. When Reuven hands Shimon the object he may be violating lifnei iver, because he is causing Shimon to benefit thereby violating lifnei iver by causing Reuven to violate ba'al yachel or do we say that you can't be in violation of lifnei iver by causing someone else to violate lifnei iver? It seems that one should be in violation of lifeni iver by causing someone else to violate lifnei iver - why should lifnei iver be any worse than any other issur. Although the gemara says in avoda zara 14a that there is no violation "lifnei d'lifnei"; that is where you provide an animal to goy#1 who will sell it to goy#2 to use for avoda zara, so the jew is 2 steps removed from the issur. In that case goy #1 is not commanded in lifnei iver, so the jew isn't violating lifnei iver by causing him to violate lifnei iver. But here since Shimon is metzuvah in lifnei iver, it would be lifnei iver for Reuven to cause him to violate lifnei iver.

Nedarim 14b - Neder not to sleep today if i sleep tomorrow

The gemara quotes a machlokes about one who makes a neder not to sleep today if he sleeps tomorrow, meaning that sleeping tomorrow is a condition that if it is done would retroactively assur him from sleeping today - there is a machlokes whether we allow him to sleep today because we are concerned he will violate his condition tomorrow.

The Ritvah asks that if one would give a get on condition that she not drink wine next week, she can get married this week and we are not concerned that she will violate her condition (the Ran in gittin elaborates about when we are and when we aren't concerned that the condition will be violated). Similarly here we should not be concerned that the condition will be violated tomorrow, and we should allow him to sleep today? Ritvah answers:

קא סבר רב יהודה דשינה דבר שאין בידו הוא וממילא אתי וחיישינן שמא תאנסנו שינה

Meaning, sleep is not something that one does actively, rather it is something that just happens. For example, one does not go to sleep during a shiur, it sort of just happens automatically.

The Mitzpah Eisan (although he doesn't quote the Ritvah) uses this concept to answer another question. Rashi implies that for violating the neder i.e. sleeping both today and tomorrow, he would receive malkus. The question is that to receive malkus one has to be warned definitively at the time of the act of issur, but here at the time of the act of issur (when he goes to sleep today), it is a hasra'as safek, since he may not sleep tomorrow and it would be totally permitted for him to sleep today. This type of warning doesn't qualify as "warning", so how can he receive malkus? He answers based on Tosafos Shabbos 4a that it is only considered hasra'as safeik if he must actively do something to make the issur go into effect, but if by being passive the issur will go into effect, then the assumption is that the issur will go into effect and it is not hasra'as safeik. Here too, sleeping tomorrow does not qualify as having to actually do something, rather we consider falling asleep to be passive so that it will automatically go into effect and create an issur on sleeping today. Therefore, the warning given before sleeping today is considered a definitive warning.

Nedarim 13 - 14 - Matfis in a davar ha'nadur not a davar ha'asur

R' Moshe points out in one of his shiurim (Dibros siman 10 anaf 2) a very fundamental machlokes why a hatfasa is only binding in a davar ha'nadur and not a davar ha'asur. Although the gemara ultimately learns this out from pesukim on 14a, it is clear from the Rishonim that there is some element of sevara necessary to interpret the pesukim (otherwise we would have darshened that you can be matfis in a davar ha'asur from the word "isur" rather than using it for something else).

The Ran understands that hatfasa can only work to transfer or apply an issur that was implemented by a person, but cannot work to transfer an issur that was placed on an object by the Torah. The issur imposed by a person is inherently different than an issur imposed by the Torah, therefore when trying to place an issur on an object one can only be matfis in an issur that was originally created by a person, and not an issur that was originally created by the Torah.

The Rambam (Nedarim 1:8) writes that "one cannot turn something which is not basar chazir into basar chazir". R' Moshe explains that it would technically be possible to transfer even an issur Torah and place it on the object of the neder, because there isn't any fundamental difference between an issur imposed by a person and an issur imposed by the Torah. The only reason hatfasa doesn't work on isurei torah such as basar chazir, is that issurei torah are not separate entities from the metzius of the object. Meaning, it is not as if there is pig meat on which the Torah places a separate status of issur; rather the Torah identifies pig meat as being assur. It is the identification of the metzius of pig meat that is assur, and therefore is not transferable to another object that is not pigs meat. A neder on the other hand is a separate issur status that is placed on the object and is easily transferable to another object.

B'kitzur - According to the Rambam an issur is totally tied to the object itself and is therefore non-transferable. According to the Ran the issur is a separate entity that the Torah places on the object, but because it is not created by a person it is not transferable.

There is a discussion whether a neder can be made on something which is already assur min hatorah like pig meat. Although the gemara says that one can make a neder on a d'var mitzvah, the ran is shavuos says that one can make a neder that will result in violation of a bitul aseh (such as a neder on matzah), but a neder will not be binding on a lo ta'aseh (like on pig meat). R' Moshe suggests that this would be dependent on the machlokes Rambam and Ran. According to the Rambam that issur neder is a chiddush that one can place a new status on an object, is makes not difference whether the object is a metzius of heter or a metzius of issur, he can still place the neder on it. But according to the Ran that an issur torah is not fundamentally different than an issur neder (just that issur torah is not created by a person and therefore not transferable), it seems logical that once there is already a status of issur torah on an object one cannot place on top of it issur neder (since they are fundamentally the same it is like an issur on an issur or a neder on a neder, that is not chal).

k'darcho ba'kodesh - R' Moshe uses this as a foundation to explain many many things - too many for this blog!

Nedarim 12a - Tevel and Teruma

The Ran and Rosh argue why Teruma is considered a davar ha'asur and not a davar ha'nadur. The Ran says that it is because it is only assur to zarim but mutar to kohanim, so long as it is not assur to all it cannot be called a davar hanadur. The Rosh and Tosafos say that since it was previously assur as tevel, by making it Teruma he is creating heter rather than issur.
R' Yossi already pointed out on this blog in yevamos that the machlokes ran and rosh may very well be the machlokes rashi and tosfos - http://hearos.blogspot.com/2007/07/86.html

Regarding the opinion of the Rosh, Tosafos here, and Rashi in Yevamos - R' Moshe (dibros heara #67) asks the obvious question that the status of Teruma creates kedusha which is assur to zarim, whereas tevel doesn't have kedusha it is just an issur that is assur to everyone. R' Moshe explains based on the Rambam (ma'achalos asuros chapt. 10) that regarding the misah bidei shamayim of tevel, it is only an issur misah if it is tevel that has teruma mixed in it, but if it is tevel wheter the teruma has been removed and only has ma'aser sheini or ma'aser ani mixed in, there is no chiyuv misah. Based on this it seems that really the chumra of misah by tevel is because of the kedushas teruma that is in it, but since it is just mixed in, it is not as severe regarding other issues i.e. tumah. According to this approach the ba'alim by seperating Teruma are not being mechadesh the kedusha status of Teruma, rather the Teruma is already there and the ba'alim is simply identifying the area where the Teruma is thereby making the remaining parts mutar as chulin.

The opinion of the Ran is also difficult - obviously if one makes a neder on an object to be assur only to some people and not others, it is considered a davar hanadur. Why then is teruma considered davar ha'asur just because it is not assur to everyone? The ran earlier on the top of the page sheds some light on this. Anytime he makes a neder that explicitly excludes some people it still is a davar hanadur. But, if his language was all inclusive, but because a gezeiras hakasuv the result of calling it "teruma" would make it mutar to some and assur to others, it is a davar ha'asur since the Torah is deciding who should be assur and who should be mutar - v'dok.