Numbers 18:23-24

²³But they of the tribe of Levi themselves shall perform the service of the tabernacle of the congregation, and they shall bear their iniquity: a statute for ever shall it be throughout your generations; and among the children of Israel shall they not possess any inheritance.

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