Numbers 8:11-13

King James Version

¹¹ And Aaron shall offer the Levites before the Lord for an offering of the children of Israel, that they may execute the service of the Lord.

¹² And the Levites shall lay their hands upon the heads of the bullocks: and thou shalt offer the one for a sin offering, and the other for a burnt offering, unto the Lord, to make an atonement for the Levites.

¹³ And thou shalt set the Levites before Aaron, and before his sons, and offer them for an offering unto the Lord.