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 8:26
8:26 They may assist their colleagues in the tent of meeting, to attend to needs, but they must do no work. This is the way you must establish the Levites regarding their duties.”