Numbers 18:8-9

The LORD gave these further instructions to Aaron: “I myself have put you in charge of all the holy offerings that are brought to me by the people of Israel. I have given all these consecrated offerings to you and your sons as your permanent share. You are allotted the portion of the most holy offerings that is not burned on the fire. This portion of all the most holy offerings—including the grain offerings, sin offerings, and guilt offerings—will be most holy, and it belongs to you and your sons.