Numbers 1:47-54

But the Levites after the tribe of their fathers were not numbered among them. For Jehovah spake unto Moses, saying, Only the tribe of Levi thou shalt not number, neither shalt thou take the sum of them among the children of Israel; but appoint thou the Levites over the tabernacle of the testimony, and over all the furniture thereof, and over all that belongeth to it: they shall bear the tabernacle, and all the furniture thereof; and they shall minister unto it, and shall encamp round about the tabernacle. And when the tabernacle setteth 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 nigh shall be put to death. And 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. But the Levites shall encamp round about the tabernacle of the testimony, that there be no wrath upon the congregation of the children of Israel: and the Levites shall keep the charge of the tabernacle of the testimony. Thus did the children of Israel; according to all that Jehovah commanded Moses, so did they.