Numbers 18:27-32

27 And your offering shall be reckoned to you as though it were the grain of the threshing floor, and as the fulness of the wine press.
28 So shall you also present an offering to the LORD from all your tithes, which you receive from the people of Israel; and from it you shall give the LORD's offering to Aaron the priest.
29 Out of all the gifts to you, you shall present every offering due to the LORD, from all the best of them, giving the hallowed part from them.'
30 Therefore you shall say to them, 'When you have offered from it the best of it, then the rest shall be reckoned to the Levites as produce of the threshing floor, and as produce of the wine press;
31 and you may eat it in any place, you and your households; for it is your reward in return for your service in the tent of meeting.
32 And you shall bear no sin by reason of it, when you have offered the best of it. And you shall not profane the holy things of the people of Israel, lest you die.'"
Revised Standard Version of the Bible, copyright 1952 [2nd edition, 1971] by the Division of Christian Education of the National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved.