Numbers 18:17-19

17But the firstborn of the ox, sheep or goat you are not to redeem. They are holy. You are to sprinkle their blood on the altar, and their fat you are to burn as a fire offering, a pleasing aroma to Adonai.

18Their meat—the breast of the wave offering and the right thigh—is yours.

19Whatever is set aside from the holy offerings which Bnei-Yisrael present to Adonai, I have given to you, your sons and your daughters with you as a permanent share. It is an everlasting covenant of salt before Adonai for you and your offspring.”