Ezra 3:8
Now in the second year of their coming to the house of God at Jerusalem, in the second month, began Zerubbabel the son of Shealtiel, and Jeshua the son of Jozadak, and the rest of their brothers the priests and the Levites, and all those who were come out of the captivity to Jerusalem, and appointed the Levites, from twenty years old and upward, to have the oversight of the work of the house of Yahweh.
Numbers 4:3
from thirty years old and upward even until fifty years old, all who enter into the service, to do the work in the Tent of Meeting.
1 Chronicles 23:4
David said, "Of these, twenty-four thousand were to oversee the work of the house of Yahweh; six thousand were officers and judges;
1 Chronicles 23:24-32
These were the sons of Levi after their fathers' houses, even the heads of the fathers' houses of those who were counted individually, in the number of names by their polls, who did the work for the service of the house of Yahweh, from twenty years old and upward.
Ezra 4:3
But Zerubbabel, and Jeshua, and the rest of the heads of fathers' [houses] of Israel, said to them, "You have nothing to do with us in building a house to our God; but we ourselves together will build to Yahweh, the God of Israel, as king Cyrus the king of Persia has commanded us."