1 Chronicles 23:24; 1 Chronicles 23:27

24 These were the sons of Levi by their fathers' houses, the heads of fathers' houses as they were listed according to the number of the names of the individuals from twenty years old and upward who were to do the work for the service of the house of the LORD.

27 For by the last words of David the sons of Levi were numbered from twenty years old and upward.