Numbers 1:51-53

51 And when the tabernacle is set out, the Levites will take it down, [48] and when encamping the tabernacle the Levites will set it up; the stranger [49] that approaches it will be put to death.

52 The Israelites [50] will encamp, each in their own camp, and each by their [51] own banner according to their divisions.

53 But the Levites will encamp around the tabernacle of the testimony, [52] and there will not be wrath on the community of the Israelites; [53] and the Levites will keep the requirements of the tabernacle of the testimony.” [54]