Numbers 18:10-20

10 As a most holy thing you shall eat it; every male may eat it; it shall be holy to you.
11 This also is yours: I have given to you, together with your sons and daughters, as a perpetual due, whatever is set aside from the gifts of all the elevation offerings of the Israelites; everyone who is clean in your house may eat them.
12 All the best of the oil and all the best of the wine and of the grain, the choice produce that they give to the Lord, I have given to you.
13 The first fruits of all that is in their land, which they bring to the Lord, shall be yours; everyone who is clean in your house may eat of it.
14 Every devoted thing in Israel shall be yours.
15 The first issue of the womb of all creatures, human and animal, which is offered to the Lord, shall be yours; but the firstborn of human beings you shall redeem, and the firstborn of unclean animals you shall redeem.
16 Their redemption price, reckoned from one month of age, you shall fix at five shekels of silver, according to the shekel of the sanctuary (that is, twenty gerahs).
17 But the firstborn of a cow, or the firstborn of a sheep, or the firstborn of a goat, you shall not redeem; they are holy. You shall dash their blood on the altar, and shall turn their fat into smoke as an offering by fire for a pleasing odor to the Lord;
18 but their flesh shall be yours, just as the breast that is elevated and as the right thigh are yours.
19 All the holy offerings that the Israelites present to the Lord I have given to you, together with your sons and daughters, as a perpetual due; it is a covenant of salt forever before the Lord for you and your descendants as well.
20 Then the Lord said to Aaron: You shall have no allotment in their land, nor shall you have any share among them; I am your share and your possession among the Israelites.