Numbers 18:10

7 But only you and your sons shall attend to your priesthood for everything concerning the altar and what is inside the veil, and you are to perform that service. I am giving you the work of the priesthood as a gift, but any outsider who comes near the sanctuary must be put to death.”

8 Then the LORD said to Aaron, “Behold, I have put you in charge of My offerings. As for all the sacred offerings of the Israelites, I have given them to you and your sons as a portion and a permanent statute.

9 A portion of the most holy offerings reserved from the fire will be yours. From all the offerings they render to Me as most holy offerings, whether grain offerings or sin offerings or guilt offerings, that part belongs to you and your sons.

10 You are to eat it as a most holy offering, and every male may eat it. You shall regard it as holy.

11 And this is yours as well: the offering of their gifts, along with all the wave offerings of the Israelites. I have given this to you and your sons and daughters as a permanent statute. Every ceremonially clean person in your household may eat it.

12 I give you all the freshest olive oil and all the finest new wine and grain that the Israelites give to the LORD as their firstfruits.

13 The firstfruits of everything in their land that they bring to the LORD will belong to you. Every ceremonially clean person in your household may eat them.