Numbers 18:24-26

24That is because I have given to the Levites the tithes that the Israelites offer to the Lord. I have told them, “You will not receive any land, like the other Israelites do.” I have given the tithes to them instead.’

25The Lord said to Moses,

26‘You must say to the Levites, “You will receive from the Israelites the tithe that I have given to you from them. I have not given any land to you. I have given the tithes to you instead. When you receive those tithes, you must offer one tenth of it to the Lord. That will be a tithe of the tithe.