As we have learned, the part of the meal offering that is sacrificed on the altar is the kometz – the fistful of flour taken by the kohen from the offering for that purpose. The Mishna on today’s daf discusses a case where the kometz became tameh – ritually defiled – and rules that if it is sacrificed in its defiled state, the offering is, nonetheless, valid, because of the power of the tzitz – the frontplate worn by the kohen gadol – to offer atonement for ritual defilement in the Temple.
The Mishna continues and teaches that this atonement is only available if the kometz becomes tameh. If, however, the problem was that it had been removed from the precincts of the Temple, then it is invalid, and the presence of the tzitz cannot atone for that difficulty.
The fact that the Mishna presented the rule in the past tense – that a ritually defiled kometz that was sacrificed – rather than stating that the kometz could be brought even under these circumstances, would seem to indicate that in this case it really should not be brought; only after-the-fact, if it was sacrificed, would it be accepted as valid. Rashi in Massekhet Gittin (54a) suggests that on a biblical level sacrificial blood that had become tameh could be sprinkled, and similarly, the kometz could be sacrificed, even le-ḥatekhila – ab initio – and it is only a rabbinic ordinance that limits this and permits it only after-the-fact. At the same time, from Rashi in Massekhet Pesaḥim 34b it appears that the tzitz only offers atonement for ritual defilement in the Temple after-the-fact, but it cannot permit sacrifices to be brought le-ḥatekhila.
It should be noted, that although the Mishna is clear that the tzitz only serves to offer atonement for ritual defilement and not for sacrifices that were taken out of the Temple, there are tanna’im who disagree. According to the Tosefta, Rabbi Akiva rules that the tzitz also has the power to offer atonement for offerings that were removed from the Temple precincts.