Numbers 18:27-32

²⁷Your contribution must be considered by you as if it were a tenth of the grain from the threshing floor or of the production from the winepress.

²⁸So you also must make a contribution to Yahweh from all the tithes that you receive from the people of Israel. From them you must give his contribution to Aaron the priest.

²⁹Out of all the gifts you receive, you must make every contribution to Yahweh. You must do this from all the best and the holiest things that have been given to you.'

³⁰Therefore you must say to them, 'When you present the best of it, then it must be credited to the Levites as the product from the threshing floor and the winepress.

³¹You may eat the rest of your gifts in any place, you and your families, because it is your pay in return for your work in the tent of meeting.

³²You will not incur any guilt by eating and drinking it, if you have presented to Yahweh the best of what you have received. But you must not profane the holy offerings of the people of Israel, or you will die.'”