Numbers 18:6-8  Amplified Bible, Classic Edition

⁶ And I, behold, I have taken your brethren the Levites from among the Israelites; to you they are a gift, given to the Lord, to do the [menial] service of the Tent of Meeting.

⁷ Therefore you and your sons with you shall attend to your priesthood for everything of the altar [of burnt offering and the altar of incense] and [of the Holy of Holies] within the veil, and you shall serve. I give you your priesthood as a service of gift. And the stranger [anyone other than Moses or your sons, Aaron] who comes near shall be put to death.^(A)

⁸ And the Lord said to Aaron, And I, behold, I have given you the charge of My heave offerings [whatever is taken out and kept of the offerings made to Me], all the dedicated and consecrated things of the Israelites; to you have I given them [as your portion] and to your sons as a continual allowance forever by reason of your anointing as priests.^(B)