Numbers 18:22-25

²²And henceforth the children of Israel shall not come nigh the tent of meeting, lest they bear sin, and die.

²³But the Levites shall do the service of the tent of meeting, and they shall bear their iniquity: it shall be a statute for ever throughout your generations; and among the children of Israel they shall have no inheritance.

²⁴For the tithe of the children of Israel, which they offer as a heave-offering unto Jehovah, I have given to the Levites for an inheritance: therefore I have said unto them, Among the children of Israel they shall have no inheritance.

²⁵And Jehovah spake unto Moses, saying,