Numbers 8:11-13

New Revised Standard Version, Anglicised Catholic Edition

¹¹ and Aaron shall present the Levites before the Lord as an elevation-offering from the Israelites, that they may perform the service of the Lord. ¹² The Levites shall lay their hands on the heads of the bulls, and he shall offer one for a sin-offering and the other for a burnt-offering to the Lord, to make atonement for the Levites. ¹³ Then you shall have the Levites stand before Aaron and his sons, and you shall present them as an elevation-offering to the Lord.