Numbers 3:7-9

New Revised Standard Version, Anglicised

⁷ They shall perform duties for him and for the whole congregation in front of the tent of meeting, doing service at the tabernacle; ⁸ they shall be in charge of all the furnishings of the tent of meeting, and attend to the duties for the Israelites as they do service at the tabernacle. ⁹ You shall give the Levites to Aaron and his descendants; they are unreservedly given to him from among the Israelites.