Numbers 8
11 Ref And Aaron is to give the Levites to the Lord as a wave offering from the children of Israel, so that they may do the Lord's work.
12 Ref And the Levites are to put their hands on the heads of the oxen, and one of the oxen is to be offered for a sin-offering and the other for a burned offering to the Lord to take away the sin of the Levites.
13 Ref Then the Levites are to be put before Aaron and his sons, to be offered as a wave offering to the Lord.
14 Ref So you are to make the Levites separate from the children of Israel, and the Levites will be mine.