Numbers 18:27-32

²⁷And the gift which ye set apart shall be reckoned unto you, as though it were the corn of the threshing-floor, and as the fulness of the wine-press.

²⁸Thus ye also shall set apart a gift unto the LORD of all your tithes, which ye receive of the children of Israel; and thereof ye shall give the gift which is set apart unto the LORD to Aaron the priest.

²⁹Out of all that is given you ye shall set apart all of that which is due unto the LORD, of all the best thereof, even the hallowed part thereof out of it.

³⁰Therefore thou shalt say unto them: When ye set apart the best thereof from it, then it shall be counted unto the Levites as the increase of the threshing-floor, and as the increase of the wine-press.

³¹And ye may eat it in every place, ye and your households; for it is your reward in return for your service in the tent of meeting.

³²And ye shall bear no sin by reason of it, seeing that ye have set apart from it the best thereof; and ye shall not profane the holy things of the children of Israel, that ye die not.'