The Bible
Numbers 8
The Levites are washed, consecrated, and set apart by the laying on of hands—They are the Lord’s in place of the firstborn of every family—They are a gift to Aaron and his sons to do the service of the tabernacle.
1And the Lord spake unto Moses, saying,
5¶ And the Lord spake unto Moses, saying,
6Take the Levites from among the children of Israel, and cleanse them.
18And I have taken the Levites for all the firstborn of the children of Israel.