Numbers 18:7

18:7 But you and your sons with you are responsible for your priestly duties, for everything at the altar and within the curtain. And you must serve. I give you the priesthood as a gift for service; but the unauthorized person who approaches must be put to death.”

Numbers 18:9

18:9 Of all the most holy offerings reserved from the fire this will be yours: Every offering of theirs, whether from every grain offering or from every purification offering or from every reparation offering which they bring to me, will be most holy for you and for your sons.