What is the source for this idea? As it was taught in a baraita: If a priest grew a wart, which temporarily disqualifies him from performing the service, his fellow priest may cut it off for him on Shabbat with his teeth. The Gemara infers: With his teeth, yes, this is permitted; but with an instrument, no, he may not do so. Likewise, for his fellow priest, yes, he may cut off his wart; but he himself, no, he may not cut off his own wart.

The Gemara inquires: According to whose opinion was this baraita taught? If you say it is in accordance with the opinion of the Rabbis, and the leniency is based on the principle that a rabbinic prohibition does not apply in the Temple, since the Rabbis say in general that biting off even one’s own nails or wart, and certainly those of another, is prohibited due to rabbinic decree, then in this case here, what is the difference to me whether it is the priest himself who cuts off the wart, or what is the difference to me whether it is another priest who cuts it off?

Rather, wasn’t it taught in accordance with the opinion of Rabbi Eliezer, who said that in general one is liable to bring a sin-offering for biting off his own nails or wart? And here, even though he maintains that preparations for a mitzva override the prohibitions of Shabbat, and it should therefore be permitted for him to cut off his own wart with an instrument, nevertheless, as much as it is possible to alter the procedure so that it does not entail the violation of a Torah prohibition, one alters, and biting off another person’s wart is prohibited due to rabbinic decree, not Torah law.

The Gemara rejects this contention: No, this is not necessarily the case. Actually, this baraita can be explained in accordance with the opinion of the Rabbis, and if the wart grew on his abdomen, or anywhere else easily removable by hand, so too, it is clear that according to the Rabbis there is no difference between himself and his fellow priest, and he may remove it himself.

However, here, we are dealing with a case where, the priest received a bite that developed into a wart on his back or on his elbow, from where he himself cannot remove it, but someone else can.

The Gemara asks: But if the baraita reflects the opinion of the Rabbis, the other priest should be permitted to remove the wart from him by hand, rather than with an instrument, and therefore one should resolve the dilemma in accordance with the teaching of Rabbi Elazar, as Rabbi Elazar said: The dispute between the Rabbis and Rabbi Eliezer with regard to the removal of one’s nails is limited to one who removed them by hand, but if he removed them with an instrument, everyone agrees that he is liable to bring a sin-offering.

The Gemara rejects this argument: And according to your reasoning, Rabbi Eliezer should also agree that he should be permitted to remove it for him by hand. The Gemara expresses surprise at this comment: What is the nature of this contention? Granted, if you say that it was taught in accordance with Rabbi Eliezer, this is why removing the wart by hand was decreed prohibited due to a preventive measure, lest he remove it with an instrument, as he maintains that removing a wart with an instrument is prohibited by the Torah. However, if you say it is according to the opinion of the Rabbis, he should be permitted to remove it for him by hand. And nothing more need be said, as it is clear that the baraita was taught in accordance with the opinion of Rabbi Eliezer.

MISHNA: With regard to a priest who was injured on his finger on Shabbat, he may temporarily wrap it with a reed so that his wound is not visible while he is serving in the Temple. This leniency applies in the Temple, but not in the country, as it also heals the wound, and medical treatment is prohibited on Shabbat due to rabbinic decree. If his intention is to draw blood from the wound or to absorb blood, it is prohibited in both places.

GEMARA: Rav Yehuda, son of Rabbi Ḥiyya, said: They taught that only a reed is permitted. However, a small sash is prohibited, as it would be considered an extra garment, and it is prohibited for a priest to add to the priestly garments prescribed by the Torah.

And Rabbi Yoḥanan said: They said that donning an extra garment is prohibited only if it is worn in a place on the priest’s body where the priestly garments are worn. But in a place where those garments are not worn, e.g., on his hand or the like, a sash that is tied there is not considered an extra garment.

The Gemara asks: And let him derive that both the reed and the sash are prohibited as an interposition. As the reed and sash interpose between the priest’s hand and the holy vessel, they should invalidate the service. The Gemara rejects this contention: Perhaps the wound is on the priest’s left hand, while the entire service is performed exclusively with his right hand. Consequently, a bandage on his left hand is not an interposition.

Alternatively, it is possible that the wound is on the priest’s right hand, but not in a place used in the service, which means the bandage does not interpose between his hand and the holy vessels used in the Temple service.

And this conclusion disputes the opinion of Rava, as Rava said that Rav Ḥisda said: In a place on the priest’s body where the priestly garments are worn, even one extra thread interposes and is prohibited, whereas in a place where the priestly garments are not worn, if the fabric was three fingerbreadths by three fingerbreadths, it interposes, but if it was less than three fingerbreadths by three fingerbreadths, it does not interpose.

The Gemara comments: This teaching certainly disagrees with the opinion of Rabbi Yoḥanan, as he maintains that the prohibition against interpositions does not apply at all in a place on the priest’s body where the priestly garments are not worn. However, shall we say that it also disagrees with the opinion of Rav Yehuda, son of Rabbi Ḥiyya, who prohibits even a sash smaller than three by three fingerbreadths?

The Gemara answers: Nothing can be proven from here, as a small sash is different, since it is significant, and it is therefore considered a garment even if it is less than three by three fingerbreadths.

According to another version, they reported this dispute as follows: Rav Yehuda, son of Rabbi Ḥiyya, said that they taught this leniency only with regard to a reed, but that a small sash interposes.

And Rabbi Yoḥanan said: They said that there is interposition with regard to an article that is less than three by three fingerbreadths only in a place where the priestly garments are worn. However, in a place where the priestly garments are not worn, the following distinction applies: