Ezra 3:8
Now in the second year after their coming to the house of God at Jerusalem, in the second month, Zerubbabel the son of Shealtiel and Jeshua the son of Jozadak made a beginning, together with the rest of their kinsmen, the priests and the Levites and all who had come to Jerusalem from the captivity. They appointed the Levites, from twenty years old and upward, to supervise the work of the house of the LORD.
Numbers 4:3
from thirty years old up to fifty years old, all who can come on duty, to do the work in the tent of meeting.
1 Chronicles 23:4
"Twenty-four thousand of these," David said,"shall have charge of the work in the house of the LORD, 6,000 shall be officers and judges
1 Chronicles 23:24-32
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.
Ezra 4:3
But Zerubbabel, Jeshua, and the rest of the heads of fathers' houses in Israel said to them, "You have nothing to do with us in building a house to our God; but we alone will build to the LORD, the God of Israel, as King Cyrus the king of Persia has commanded us."