Numbers 8:20-22 New Revised Standard Version, Anglicised Catholic Edition (NRSVACE)
20 Moses and Aaron and the whole congregation of the Israelites did with the Levites accordingly; the Israelites did with the Levites just as the Lord had commanded Moses concerning them. 21 The Levites purified themselves from sin and washed their clothes; then Aaron presented them as an elevation-offering before the Lord, and Aaron made atonement for them to cleanse them. 22 Thereafter the Levites went in to perform their service in the tent of meeting in attendance on Aaron and his sons. As the Lord had commanded Moses concerning the Levites, so they dealt with them.