Numbers 3:31

3:31 Their responsibilities included the ark, the table, the lampstand, the altars, and the utensils of the sanctuary with which they ministered, the curtain, and all their service.

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 18:2

18:2 “Bring with you your brothers, the tribe of Levi, the tribe of your father, so that they may join with you and minister to you while you and your sons with you are before the tent of the testimony.