1 Chronicles (Author Compiled by Isaiah and Ezra from records of Nathan, Gad, Iddo, Ahijah, Jehu and others.)
23:24These were the sons of Levi according to their fathers' houses, the chief fathers, as they were reckoned, by number of names by their polls, who did the work of the service of the house of Jehovah, from twenty years old and upward.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.