Numbers 18:17-19

17But you must not redeem the firstborn of a cow or a sheep or a goat; they are holy. You must splash their blood on the altar and burn their fat for an offering made by fire for a pleasing aroma to the Lord.

18And their meat will be yours, just as the breast and the right hip of the raised offering is yours.

19All the raised offerings of the holy things that the Israelites offer to the Lord, I have given to you, and to your sons and daughters with you, as a perpetual ordinance. It is a covenant of salt forever before the Lord for you and for your descendants with you.”