Numbers 8:6-14

6“Take the Levites from among all the Israelites and make them ceremonially clean. 7To purify them, do this: Sprinkle the water of cleansing on them; then have them shave their whole bodies and wash their clothes. And so they will purify themselves. 8Have them take a young bull with its grain offering of the finest flour mixed with olive oil; then you are to take a second young bull for a sin offering. 9Bring the Levites to the front of the tent of meeting and assemble the whole Israelite community. 10You are to bring the Levites before the Lord, and the Israelites are to lay their hands on them. 11Aaron is to present the Levites before the Lord as a wave offering from the Israelites, so that they may be ready to do the work of the Lord. 12“Then the Levites are to lay their hands on the heads of the bulls, using one for a sin offering to the Lord and the other for a burnt offering, to make atonement for the Levites. 13Have the Levites stand in front of Aaron and his sons and then present them as a wave offering to the Lord. 14In this way you are to set the Levites apart from the other Israelites, and the Levites will be mine.