Deuteronomy 18:8 (KJV)

And this shall be the priest's due from the people, from them that offer a sacrifice, whether it be ox or sheep; and they shall give unto the priest the shoulder, and the two cheeks, and the maw.

The firstfruit also of thy corn, of thy wine, and of thine oil, and the first of the fleece of thy sheep, shalt thou give him.

For the LORD thy God hath chosen him out of all thy tribes, to stand to minister in the name of the LORD, him and his sons for ever.

And if a Levite come from any of thy gates out of all Israel, where he sojourned, and come with all the desire of his mind unto the place which the LORD shall choose;

Then he shall minister in the name of the LORD his God, as all his brethren the Levites do, which stand there before the LORD.

When thou art come into the land which the LORD thy God giveth thee, thou shalt not learn to do after the abominations of those nations.

There shall not be found among you any one that maketh his son or his daughter to pass through the fire, or that useth divination, or an observer of times, or an enchanter, or a witch.

Or a charmer, or a consulter with familiar spirits, or a wizard, or a necromancer.

For all that do these things are an abomination unto the LORD: and because of these abominations the LORD thy God doth drive them out from before thee.

Thou shalt be perfect with the LORD thy God.