Numbers 18:6-9

⁶And I have taken your brethren the Levites out of the midst of the children of Israel, a present given to the Lord, to minister in the services of the tabernacle of witness.

⁷And you and your sons after you shall keep up your priestly ministration, according to the whole manner of the altar, and that which is within the veil; and you° shall minister in the services as the office of your priesthood; and the stranger that comes near shall die.

⁸And the Lord said to Aaron, And, behold, I have given you the charge of the first fruits of all things consecrated to me by the children of Israel; and I have given them to you as an honour, and to your sons after you for a perpetual ordinance.

⁹And let this be to you from all the holy things that are consecrated to me, even the burnt offerings, from all their gifts, and from all their sacrifices, and from every trespass-offering of theirs, and from all their sin-offerings, whatever things they give to me of all their holy things, they shall be your and your sons'.