Numbers 18:6-7 ▼

6 And behold, I Myself have taken your brothers the Levites from among the sons of Israel; they are a gift to you, given to Yahweh, to perform the service for the tent of meeting.

7 But you and your sons with you shall keep your priesthood in everything that concerns the altar and inside the veil, and you are to perform service. I am giving you the priesthood as a bestowed service, but the outsider who comes near shall be put to death.”