Sanhedrin 18a - Kohen Gadol Following the Deceased

The Mishna quotes a machlokes regarding a kohen gadol walking behind the coffin in the funeral procession. R. Meir (as explained by Rashi) holds that he can't be within the same courtyard because he may come to touch the coffin and make himself ta'mei, thereby violating a l'av. The Gemara 19a says that according to R. Meir the pasuk of ומן המקדש לא יצא, means that he should not leave his status of kedusha. The gemara implies that the necessary distance is that they shouldn't be in the same alleyway, because the distance will serve as an indicator to prevent him from touching the coffin. The simple reading of the gemara implies that the Torah violation is only when he touches the coffin and makes himself ta'mei, just that the Rabbonon insist on a greater distance. However, Rashi in the mishna and the gemara clearly writes that the Torah violation of not leaving his kedusha demands that he create a safeguard to prevent the possibility of becoming ta'mei. This seems to be a situation where we have a mitzva d'oraysa that serves as a safeguard for another mitzva d'oraysa. The Torah requires that he take precaution to prevent tu'mah.

R. Yehuda argues and holds that the pasuk ומן המקדש לא יצא, means at it sounds literally that he shouldn't leave the mikdash at all to follow the deceased. Rashi on the Mishna writes that R. Yehuda reads the pasuk literally and rejects R. Meir's understanding of מקדושתו לא יצא. However, the gemara 19a seems to understand that R. Yehuda reads the pasuk exactly as R. Meir does, just that he considers it necessary to make a greater safeguard that completely prevents him from following after the deceased because in his depression over the loss he won't be so aware of how close he is to the dead. The Rashash also raises this question. It seems that Rashi in the mishna understands that R. Yehuda in the gemara is just responding to the opinion of R. Meir. Even if R. Meir is correct in how he understands the pasuk, there would still be an issur even to follow after the meis from a distance.

The Ramban in Chumash (21:12) disagrees with Rashi and understands that according to both opinions the entire prohibition of following after the coffin is only d'rabonon, as the language of the gemara implies. Therefore, the issur only applies to his own relative where he is likely to be drawn close to and come into physical contact with, but doesn't apply to others. The actual pasuk is coming to say that when the kohen gadol is doing the avoda, he cannot stop what he is doing and leave for a meis because it is degrading to the avoda. The Ramban writes explicitly that a kal v'chomer can be made to a kohen gadol leaving in the middle of the avoda for some other purpose.