Numbers 3:7-9

Young's Literal Translation

⁷ and kept his charge, and the charge of all the company before the tent of meeting, to do the service of the tabernacle;

⁸ and they have kept all the vessels of the tent of meeting, and the charge of the sons of Israel, to do the service of the tabernacle;

⁹ and thou hast given the Levites to Aaron and to his sons; they are surely given to him out of the sons of Israel.