Numbers 18:4-6

American Standard Version

⁴ And they shall be joined unto thee, and keep the charge of the tent of meeting, for all the service of the Tent: and a stranger shall not come nigh unto you. ⁵ And ye shall keep the charge of the sanctuary, and the charge of the altar; that there be wrath no more upon the children of Israel. ⁶ And I, behold, I have taken your brethren the Levites from among the children of Israel: to you they are a gift, given unto Jehovah, to do the service of the tent of meeting.