Numbers 18:26-32

“Moreover, you shall speak to the Levites and say to them, ‘When you take from the Israelites the tithe which I have given to you from them as your inheritance, then you shall present an offering from it to the LORD, a tithe of the tithe [paid by the people]. Your offering shall be credited to you as the grain from the threshing floor or as the full produce from the wine vat. Likewise you shall also present an offering to the LORD from all your tithes, which you receive from the Israelites; and from it you shall give the LORD’S offering to Aaron the priest. Out of all your gifts, you shall present every offering due to the LORD, from all the best of it, even the sacred part from them.’ Therefore you shall say to them, ‘When you have offered the best from it, then the rest shall be credited to the Levites as the product of the threshing floor, and as the product of the wine vat. You may eat it anywhere, you and [the members of] your households, for it is your compensation in return for your service in the Tent of Meeting (tabernacle). You will bear no sin because of it when you have offered the best of it; but you shall not profane the sacred gifts of the children of Israel, or you will die [because of it].’ ”