1 Chronicles 23:24 ¶These were the sons of Levi after the house of their fathers; even the chief of the fathers, as they were counted by number of names by their polls, that did the work for the service of the house of the LORD, from the age of twenty years and upward.

1 Chronicles 23:27 For by the last words of David the Levites were numbered from twenty years old and above:

Numbers 8:24 This is it that belongeth unto the Levites: from twenty and five years old and upward they shall go in to wait upon the service of the tabernacle of the congregation:

Numbers 4:3 From thirty years old and upward even until fifty years old, all that enter into the host, to do the work in the tabernacle of the congregation.