Numbers 1:49

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

48For the LORD spoke to Moses, saying,

49“Only the tribe of Levi you shall not count, neither shall you take a census of them among the children of Israel;

50but appoint the Levites over the Tabernacle of the Testimony, and over all its furnishings, and over all that belongs to it. They shall carry the tabernacle and all its furnishings; and they shall take care of it, and shall encamp around it.

51When the tabernacle is to move, the Levites shall take it down; and when the tabernacle is to be set up, the Levites shall set it up. The stranger who comes near shall be put to death.