Numbers 18:30-32

30Therefore 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.

31You 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).

32You 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].’ ”