Numbers 18:7-9 Revised Standard Version Catholic Edition (RSVCE)
7 And you and your sons with you shall attend to your priesthood for all that concerns the altar and that is within the veil; and you shall serve. I give your priesthood as a gift,[a] and any one else who comes near shall be put to death.”
The Priests’ Portion
8 Then the Lord said to Aaron, “And behold, I have given you whatever is kept of the offerings made to me, all the consecrated things of the people of Israel; I have given them to you as a portion, and to your sons as a perpetual due. 9 This shall be yours of the most holy things, reserved from the fire; every offering of theirs, every cereal offering of theirs and every sin offering of theirs and every guilt offering of theirs, which they render to me, shall be most holy to you and to your sons.