Numbers 1:47-53

47But the Levites after the tribe of their fathers were not numbered among them. 48For the LORD had spoken to Moses, saying, 49Only thou shalt not number the tribe of Levi, neither take the sum of them among the children of Israel: 50But thou shalt appoint the Levites over the tabernacle of testimony, and over all its vessels, and over all things that belong to it: they shall bear the tabernacle, and all its vessels; and they shall minister to it, and shall encamp around the tabernacle. 51And when the tabernacle moveth forward, the Levites shall take it down: and when the tabernacle is to be pitched, the Levites shall set it up: and the stranger that cometh near shall be put to death. 52And the children of Israel shall pitch their tents, every man by his own camp, and every man by his own standard, throughout their hosts. 53But the Levites shall encamp around the tabernacle of testimony, that there may be no wrath upon the congregation of the children of Israel: and the Levites shall keep the charge of the tabernacle of testimony.