Numbers 18:6-8
Darby Translation
6 And I, behold, I have taken your brethren, the Levites, from among the children of Israel; to you are they given as a gift for Jehovah to perform the service of the tent of meeting.
7 But thou and thy sons with thee shall attend to your priesthood for all that concerneth the altar, and for that which is inside the veil; and ye shall perform the service: I give you your priesthood as a service of gift, and the stranger that cometh near shall be put to death.
8 And Jehovah spoke to Aaron, And I, behold, I have given thee the charge of my heave-offerings, of all the hallowed things of the children of Israel; to thee have I given them, because of the anointing, and to thy sons by an everlasting statute.
Read full chapterPublic Domain (Why are modern Bible translations copyrighted?)