Numbers 1:50

1:50 But appoint the Levites over the tabernacle of the testimony, over all its furnishings and over everything in it. They must carry the tabernacle and all its furnishings; and they must attend to it and camp around it.

Numbers 18:23

18:23 But the Levites must perform the service of the tent of meeting, and they must bear their iniquity. It will be a perpetual ordinance throughout your generations that among the Israelites the Levites have no inheritance.