Exodus 29:28
28 It shall be for Aaron and his sons as a perpetual due from the people of Israel, for it is a contribution. It shall be a econtribution from the people of Israel from their peace offerings, their contribution to the Lord.
Leviticus 7:34
34 For dthe breast that is waved and the thigh that is contributed I have taken from the people of Israel, out of the sacrifices of their peace offerings, and have given them to Aaron the priest and to his sons, as a perpetual due from the people of Israel.
Numbers 18:19
19 All the holy contributions that the people of Israel present to the Lord I give to you, and to your sons and daughters with you, as a perpetual due. It is a rcovenant of salt forever before the Lord for you and for your offspring with you.”