Numbers 18:22-23

²²Neyther shall the children of Israel any more come neere the Tabernacle of the Congregation, lest they susteine sinne, and die.

²³But the Leuites shall do the seruice in the Tabernacle of the Congregation, and they shall beare their sinne: it is a law for euer in your generations, that among the children of Israel they possesse none inheritance.