Numbers 18:21-29

As 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. “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. Only 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, because I have given them the Israelites’ tithes, which have been presented as sacred offerings to the LORD. This will be the Levites’ share. That is why I said they would receive no allotment of land among the Israelites.” The LORD also told Moses, “Give these instructions to the Levites: When you receive from the people of Israel the tithes I have assigned as your allotment, give a tenth of the tithes you receive—a tithe of the tithe—to the LORD as a sacred offering. The LORD will consider this offering to be your harvest offering, as though it were the first grain from your own threshing floor or wine from your own winepress. You must present one-tenth of the tithe received from the Israelites as a sacred offering to the LORD. This is the LORD’s sacred portion, and you must present it to Aaron the priest. Be sure to give to the LORD the best portions of the gifts given to you.