Numbers 1:50

47 But the Levites after the tribe of their fathers were not numbered among them.

48 For Yahweh spoke to Moses, saying,

49 Only the tribe of Levi you shall not number, neither shall you take the sum of them among the children of Israel;

50 but appoint you the Levites over the tent of the testimony, and over all the furniture of it, and over all that belongs to it: they shall bear the tent, and all the furniture of it; and they shall minister to it, and shall encamp round about the tent.

51 When the tent sets forward, the Levites shall take it down; and when the tent is to be pitched, the Levites shall set it up: and the stranger who comes near shall be put to death.

52 The children of Israel shall pitch their tents, every man by his own camp, and every man by his own standard, according to their hosts.

53 But the Levites shall encamp round about the tent of the testimony, that there be no wrath on the congregation of the children of Israel: and the Levites shall keep the charge of the tent of the testimony.