with regard to a blemished priest, who may partake of the meat of offerings, if he performed sacrificial rites he has desecrated the service, then with regard to an acute mourner, who may not partake of the meat of offerings, is it not right that if he performed sacrificial rites he has desecrated the service?

The Gemara rejects the inference: One cannot derive this halakha from the case of a blemished priest, as what is notable about a blemished priest? It is notable in that the Torah rendered animals that are sacrificed like the priests who sacrifice them. Since this stringency does not exist with regard to acute mourning, perhaps an acute mourner may perform sacrificial rites as well.

The Gemara responds: The case of a non-priest will prove that this is no reason to reject the a fortiori inference, since there is no equivalence between priest and sacrifice in this regard, yet a non-priest desecrates the service. The Gemara rejects this as well: One cannot cite a proof from the case of a non-priest, as what is notable about the case of a non-priest? It is notable in that he has no remedy, i.e., a non-priest may never perform the sacrificial rites. By contrast, an acute mourner will eventually become permitted to perform the service.

The Gemara responds: A blemished priest will prove that this is no reason to reject the inference, as even though the priest may perform the service if the blemish is healed, he desecrates the service so long as he remains blemished. And the inference has reverted to its starting point. Therefore, one learns the halakha from the combination of the cases of a blemished priest and a non-priest: The aspect of this case is not like the aspect of that case, and the aspect of that case is not like the aspect of this case. Their common element is that they are prohibited from performing sacrificial rites, and if they performed such rites they have desecrated the service. Therefore, I will also include an acute mourner, who is prohibited from performing sacrificial rites, and conclude that if he performed sacrificial rites he has desecrated the service.

The Gemara clarifies: Where is an acute mourner prohibited from performing sacrificial rites, as asserted in the inference? If we say that it is derived from the verse: “And he shall not leave the Sanctuary, and he will not profane the Sanctuary of his God” (Leviticus 21:12), then the above a fortiori inference is unnecessary, since profanation itself is written in the verse. Rather, it must be that it is derived from the verse: “This day have they offered their sin offering?” (Leviticus 10:19), and this tanna holds that the sin offering brought by Aaron was burned because Aaron and his sons were in acute mourning.

The Gemara challenges: The inference from the common element of the cases of a blemished priest and a non-priest can be refuted: What is notable about their common element? It is notable in that there are no circumstances in which its general prohibition was permitted. There is an exception to the prohibition against an acute mourner performing the Temple service, namely the High Priest, who may perform the sacrificial rites while an acute mourner.

The Gemara responds: The case of an impure priest will prove that this is no reason to reject the inference, as there is an exception to the prohibition against performing the service while impure, namely that the prohibition against performing the Temple service in a state of impurity is permitted in cases involving the public, yet an impure priest desecrates the service.

The Gemara asks: What is notable about the case of an impure priest? It is notable in that he imparts impurity to others. Perhaps it is only for this reason that an impure priest desecrates the service. The Gemara responds: Those other cases, i.e., a blemished priest and a non-priest, will prove that this does not reject the inference, since they do not impart their status to others. And the inference has reverted to its starting point. Therefore, one can derive the halakha from the combination of the cases of an impure priest, a blemished priest, and a non-priest: The aspect of this case is not like the aspect of that case; their common element is that they are prohibited from performing sacrificial rites and they desecrate the service. Therefore, I will also conclude that since an acute mourner is prohibited from performing sacrificial rites, he desecrates the service.

The Gemara asks: But let one refute this as well: What is notable about their common element? It is notable in that its general prohibition was not permitted, even in the case of a High Priest performing rites for an individual’s offering. By contrast, a High Priest in acute mourning may perform rites even for individual offerings. The Gemara responds: The category of impurity, at least, is permitted in the case of communal offerings. Therefore, one cannot claim that an impure priest, a non-priest, and a blemished priest all share a lack of exemptions.

Rav Mesharshiyya says: The halakha with regard to an acute mourner is derived by a fortiori inference from the case of a sitting priest: And just as with regard to a sitting priest, who may partake of the meat of offerings, if he performed sacrificial rites he has desecrated the service, then with regard to an acute mourner, who may not partake of the meat of offerings, is it not right that if he performed sacrificial rites he has desecrated the service?

The Gemara rejects this: What is notable about the case of a sitting priest? It is notable in that one who sits is disqualified from bear-ing witness, as witnesses must stand when testifying. The Gemara responds: Learn instead from the halakha of a sitting Torah scholar, as the court may allow a Torah scholar to sit while testifying.

The Gemara challenges: Still, one cannot derive from this, as what is notable about the category of a sitting priest? It is notable in that generally speaking, one who sits is disqualified from bearing witness, even though there are exceptions. The Gemara responds: The category of a sitting priest cannot refute the derivation. One can refute a derivation only from concrete cases, not general concepts. And even if you say it can refute the derivation, the halakha with regard to a non-priest can be derived from the case of a sitting priest and from one of those other cases, i.e., a non-priest, an impure priest, or a blemished priest, through their common element.

§ The mishna teaches that if an acute mourner collects the blood of an offering, the offering is disqualified. Rava says: They taught this only with regard to an individual’s offering. But with regard to a communal offering, a rite performed by an acute mourner does effect acceptance. One can derive this by a fortiori inference from ritual impurity.

Just as the prohibition against performing rites in a state of ritual impurity, whose general prohibition was not permitted in the case of a High Priest performing rites for an individual’s offering, as no individual offering may be sacrificed in a state of impurity, was nevertheless permitted in the case of an ordinary [hedyot] priest performing rites for a communal offering, as communal offerings may be sacrificed by an impure priest when necessary; then so too, with regard to the prohibition against performing rites while in a period of acute mourning, whose general prohibition was permitted in the case of a High Priest performing rites for an individual’s offering, as the High Priest may perform all rites while an acute mourner, is it not right that this prohibition was permitted in the case of an ordinary priest performing rites for a communal offering?

Rava bar Ahilai objects to this: On the contrary, if such an inference can be made, then perhaps one can make the following mistaken inference: The performance of rites in a state of acute mourning should not be permitted in the case of a High Priest performing rites for an individual’s offering, by a fortiori inference: And just as the prohibition against performing rites in a state of ritual impurity, whose general prohibition was permitted in the case of an ordinary priest performing rites for a communal offering, was not permitted in the case of a High Priest performing rites for an individual’s offering; then so too, with regard to the prohibition against performing the rites during a period of acute mourning, whose general prohibition was not permitted in the case of an ordinary priest performing rites for a communal offering, is it not right that this prohibition should not be permitted in the case of a High Priest performing rites for an individual’s offering?

And similarly, one may claim: The performance of rites in a state of ritual impurity should be permitted in the case of a High Priest performing rites for an individual’s offering, by a fortiori inference: And just as the prohibition against performing rites in a state of acute mourning, whose general prohibition was not permitted in the case of an ordinary priest performing rites for a communal offering, still was permitted in the case of a High Priest performing rites for an individual’s offering; then so too, with regard to the prohibition against performing the rites in a state of ritual impurity, whose general prohibition was permitted in the case of an ordinary priest performing rites for a communal offering, is it not right that this prohibition was permitted in the case of a High Priest performing rites for an individual’s offering?

And similarly, one may claim: The performance of rites in a state of ritual impurity should not be permitted in the case of an ordinary priest performing rites for a communal offering, by a fortiori inference: And just as the prohibition against performing rites in a state of acute mourning, whose general prohibition was permitted in the case of a High Priest performing rites for an individual’s offering, still was not permitted in the case of an ordinary priest performing rites for a communal offering; then so too, with regard to the prohibition against performing the rites in a state of ritual impurity, whose general prohibition was not permitted in the case of a High Priest performing rites for an individual offering, is it not right that this prohibition should not be permitted in the case of an ordinary priest performing rites for a communal offering?

The Gemara provides a mnemonic for recalling the above rejections of Rava bar Ahilai: And should not be permitted, and should not be permitted, acute mourning, and ritual impurity, ritual impurity, individual, and individual, communal.