Leviticus 7:20

וטמאתו עליו [BUT THE SOUL THAT EATETH OF THE FLESH OF THE SACRIFICES …] HAVING ITS (or HIS) UNCLEANNESS UPON IT (or HIM) — Scripture is speaking here of the uncleanness of the person (i.e., the words mean: And the soul (person) that eateth of the flesh of the שלמים whilst his uncleanness is upon him; it does not mean: the person who eateth the flesh whilst its uncleanness is upon it) (Sifra, Tzav, Chapter 14 3; Zevachim 43b; cf. Rashi on Leviticus 22:3). But a clean person who eats unclean sacrificial flesh is not punished with excision, as is the case here, but only for transgressing the prohibition in v. 19:“And the flesh, that toucheth any unclean thing [shall not be eaten]”, for which the punishment is lashes. The prohibition referring to the case of “an unclean person who eats holy things” for which our text states the punishment is not expressly mentioned in the Torah but the Sages derived it by means of a verbal analogy (ג"ש) (Makkot 14b). — Three times is the punishment of excision stated in the Torah with reference to people eating holy sacrifices in a state of bodily uncleanness, (here, in v. 21 and in Leviticus 22:3), and our Rabbis explained them in Treatise Shevuot 7a as follows: one is intended as a general statement, the other as referring to a particular case and the third is intended to teach about the קרבן עולה ויורד (the sacrifice of higher or lesser value according to monetary circumstances of him who offers it; Leviticus 5:2, 3), that it is prescribed only as an atonement for communicating uncleanness to the Temple or sacred food by entering the former or eating the latter in a state of uncleanness (cf. Rashi on Leviticus 22:3 and Note thereon).

וְהַנֶּ֜פֶשׁ אֲשֶׁר־תֹּאכַ֣ל בָּשָׂ֗ר מִזֶּ֤בַח הַשְּׁלָמִים֙ אֲשֶׁ֣ר לַיהֹוָ֔ה וְטֻמְאָת֖וֹ עָלָ֑יו וְנִכְרְתָ֛ה הַנֶּ֥פֶשׁ הַהִ֖וא מֵעַמֶּֽיהָ׃

But the person that eats of the flesh of the sacrifice of peace offerings, that pertain to the Lord, having his uncleanness upon him, that soul shall be cut off from his people.