Numbers 18:8, 19

Then the LORD spoke to Aaron, “Now behold, I Myself have given you charge of My offerings, even all the holy gifts of the sons of Israel I have given them to you as a portion and to your sons as a perpetual allotment.

All the offerings of the holy gifts, which the sons of Israel offer to the LORD, I have given to you and your sons and your daughters with you, as a perpetual allotment. It is an everlasting covenant of salt before the LORD to you and your descendants with you.”