Numbers 18:20-23

20And the Lord said to Aaron, “You priests will receive no allotment of land or share of property among the people of Israel. I am your share and your allotment.

21As for the tribe of Levi, your relatives, I will compensate them for their service in the Tabernacle. Instead of an allotment of land, I will give them the tithes from the entire land of Israel.

22“From now on, no Israelites except priests or Levites may approach the Tabernacle. If they come too near, they will be judged guilty and will die.

23Only the Levites may serve at the Tabernacle, and they will be held responsible for any offenses against it. This is a permanent law for you, to be observed from generation to generation. The Levites will receive no allotment of land among the Israelites,