Numbers 18:9, 19

You are to have the part of the most holy offerings that is kept from the fire. From all the gifts they bring me as most holy offerings, whether grain or sin or guilt offerings, that part belongs to you and your sons.

Whatever is set aside from the holy offerings the Israelites present to the LORD I give to you and your sons and daughters as your perpetual share. It is an everlasting covenant of salt before the LORD for both you and your offspring.”