Numbers 18:6-9

⁶'And I, lo, I have taken your brethren the Levites from the midst of the sons of Israel; to you a gift they are given by Jehovah, to do the service of the tent of meeting;

⁷and thou, and thy sons with thee, do keep your priesthood, for everything of the altar, and within the vail, and ye have served; a service of gift I make your priesthood; and the stranger who is coming near is put to death.'

⁸And Jehovah speaketh unto Aaron: 'And I, lo, I have given to thee the charge of My heave-offerings, of all the hallowed things of the sons of Israel — to thee I have given them for the anointing, and to thy sons, by a statute age-during.

⁹This is thine of the most holy things, from the fire: all their offering, to all their present, and to all their sin-offering, and to all their guilt-offering, which they give back to Me, is most holy to thee, and to thy sons;