Numbers 1:47-51

The Levites, however, were not counted by their ancestral family along with the others. GOD had told Moses, “The tribe of Levi is an exception: Don’t register them. Don’t count the tribe of Levi; don’t include them in the general census of the People of Israel. Instead, appoint the Levites to be in charge of The Dwelling of The Testimony—over all its furnishings and everything connected with it. Their job is to carry The Dwelling and all its furnishings, maintain it, and camp around it. When it’s time to move The Dwelling, the Levites will take it down, and when it’s time to set it up, the Levites will do it. Anyone else who even goes near it will be put to death.