Numbers 3:7

3:7 They are responsible for his needs and the needs of the whole community before the tent of meeting, by attending to the service of the tabernacle.

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.”

Numbers 18:5

18:5 You will be responsible for the care of the sanctuary and the care of the altar, so that there will be no more wrath on the Israelites.