Ezra 3:8
And in the second year of their coming in unto the house of God, to Jerusalem, in the second month, began Zerubbabel son of Shealtiel, and Jeshua son of Jozadak, and the remnant of their brethren the priests and the Levites, and all those coming from the captivity to Jerusalem, and they appoint the Levites from a son of twenty years and upward, to overlook the work of the house of Jehovah.
Numbers 4:3
from a son of thirty years and upward, even till a son of fifty years, every one going in to the host, to do work in the tent of meeting.
1 Chronicles 23:4
Of these to preside over the work of the house of Jehovah are twenty and four thousand, and officers and judges six thousand,
1 Chronicles 23:24-32
These are sons of Levi, by the house of their fathers, heads of the fathers, by their appointments, in the number of names, by their polls, doing the work for the service of the house of Jehovah, from a son of twenty years and upward,
Ezra 4:3
And Zerubbabel saith to them, also Jeshua, and the rest of the heads of the fathers of Israel, 'Not for you, and for us, to build a house to our God; but we ourselves together do build to Jehovah God of Israel, as the king Cyrus, king of Persia, commanded us.'