Numbers 4:23 from thirty years and upward to fifty years old, you shall number them; all who enter to perform the service to do the work in the tent of meeting.

Numbers 4:30 from thirty years and upward even to fifty years old, you shall number them, everyone who enters the service to do the work of the tent of meeting.

Numbers 8:24 "This is what applies to the Levites: from twenty-five years old and upward they shall enter to perform service in the work of the tent of meeting.

1 Chronicles 23:3 The Levites were numbered from thirty years old and upward, and their number by census of men was 38,000.

1 Chronicles 23:24 These were the sons of Levi according to their fathers' households, even the heads of the fathers' households of those of them who were counted, in the number of names by their census, doing the work for the service of the house of the LORD, from twenty years old and upward.

Ezra 3:8 Now in the second year of their coming to the house of God at Jerusalem in the second month, Zerubbabel the son of Shealtiel and Jeshua the son of Jozadak and the rest of their brothers the priests and the Levites, and all who came from the captivity to Jerusalem, began the work and appointed the Levites from twenty years and older to oversee the work of the house of the LORD. (NASB ©1995)