Zevachim 99A

גמ׳ מנא הני מילי? אמר ריש לקיש, דאמר קרא: ״הכהן המחטא אתה יאכלנה״⁠ – כהן המחטא יאכל, שאינו מחטא אינו אוכל.

Talmud: The Mishnah teaches that a priest who is unfit for the Temple service does not receive a share of the sacrificial meat. The Talmud asks: From where are these matters derived? Reish Lakish said: It is derived from a verse, as the verse states about a sin offering: “The priest who effects atonement should eat it; in a sacred place should it be eaten, in the court of the Tent of Meeting” (Leviticus 6:19). This teaches that only a priest who effects atonement by performing the rites of the offering should partake of its meat, but a priest who does not effect atonement does not partake of its meat.

וכללא הוא?! והרי משמרה כולה ⁠– דאין מחטאין, ואוכלין! ראוי לחיטוי קאמרינן.

The Talmud challenges: And is this an established principle? But there are all the priests of the priestly watch of that week in the Temple, who do not effect atonement for that offering, because the blood of a specific sin offering is presented by just one priest, and yet they all partake of its meat. The Talmud explains: We mean to say that any priest who is fit for effecting atonement may partake of it, even one who did not participate in the service.

הרי קטן ⁠– דאינו ראוי לחיטוי, ואוכל! אלא מאי ״יאכלנה״⁠ – יחלקנה. ראוי לחיטוי ⁠– חולק, שאינו ראוי לחיטוי ⁠– אינו חולק.

The Talmud objects: But there is the case of a minor, who is unfit for effecting atonement, and who nevertheless partakes of sacrificial meat. The Talmud explains: Rather, what is meant by the term: “should eat it”? It means that he should receive a share of it. The halakha is therefore that a priest who is fit for effecting atonement receives a share of the meat, but a priest who is unfit for effecting atonement does not receive a share of the meat. Minors do not receive a share, though they may partake of meat given to them by others.