וּמִשְׁפַּ֥ט הַכֹּהֲנִ֖ים אֶת־הָעָ֑ם כָּל־אִ֞ישׁ זֹבֵ֣חַ זֶ֗בַח וּבָ֨א נַ֤עַר הַכֹּהֵן֙ כְּבַשֵּׁ֣ל הַבָּשָׂ֔ר וְהַמַּזְלֵ֛ג שְׁלֹ֥שׁ־הַשִּׁנַּ֖יִם בְּיָדֽוֹ׃
祭司們對待百姓的慣例是這樣：凡有人獻祭，在煮肉的時候，祭司的僕人就手拿三齒的叉子來，
Rashi
The custom of the kohanim. They established this law for themselves, since they rightfully inherited only the breast and the thigh of the peace offering.