Mishnayos Chullin Perek 10 Mishnah 1

The mitzva to give the foreleg, the jaw, and the maw of slaughtered animals to the priests, known as the gifts of the priesthood, applies both in Eretz Yisrael and outside of Eretz Yisrael, in the presence of the Temple and not in the presence of the Temple, and it applies to non-sacred animals, but not to sacrificial animals. It is necessary to emphasize that it does not apply to sacrificial animals, as by right it should be inferred a fortiori: If non-sacred animals, which are not obligated to have the breast and thigh taken from them and given to the priest, are obligated to have gifts of the priesthood given from them, then with regard to sacrificial animals, which are obligated to have the breast and thigh given from them, is it not right that they should be obligated to have gifts of the priesthood given from them? Therefore, the verse states: “For the breast of waving and the thigh of giving I have taken of the children of Israel from the sacrifice of the peace offerings, and have given them to Aaron the priest and to his sons as a due forever from the children of Israel” (Leviticus 7:34), from which it is derived that the priest has only that which is stated with regard to that matter, i.e., the breast and the thigh, and not the foreleg, the jaw and the maw.

הַזְּרוֹעַ וְהַלְּחָיַיִם וְהַקֵּבָה נוֹהֲגִין בָּאָרֶץ וּבְחוּצָה לָאָרֶץ, בִּפְנֵי הַבַּיִת וְשֶׁלֹּא בִפְנֵי הַבַּיִת, בְּחֻלִּין אֲבָל לֹא בְמֻקְדָּשִׁין. שֶׁהָיָה בַדִּין, וּמָה אִם הַחֻלִּין, שֶׁאֵינָן חַיָּבִין בְּחָזֶה וָשׁוֹק, חַיָּבִין בַּמַּתָּנוֹת, קָדָשִׁים שֶׁחַיָּבִין בְּחָזֶה וָשׁוֹק, אֵינוֹ דִין שֶׁחַיָּבִין בַּמַּתָּנוֹת. תַּלְמוּד לוֹמַר (ויקרא ז), וָאֶתֵּן אֹתָם לְאַהֲרֹן הַכֹּהֵן וּלְבָנָיו לְחָק עוֹלָם, אֵין לוֹ אֶלָּא מַה שֶּׁאָמוּר בָּעִנְיָן: