Numbers 18:21-24

21“To the sons of Levi, behold, I have given all the 1tithe in Israel for an inheritance, in return for their service which they perform, the service of the tent of meeting. 222The sons of Israel shall not come near the tent of meeting again, or they will bear sin and die. 23Only the Levites shall perform the service of the tent of meeting, and they shall 3bear their iniquity; it shall be a perpetual statute throughout your generations, and among the sons of Israel 4they shall have no inheritance. 24For the tithe of the sons of Israel, which they offer as an offering to the Lord, I have given to the Levites for an inheritance; therefore I have said concerning them, ‘5They shall have no inheritance among the sons of Israel.’”