Ezra 3:8
Now in the second year of their coming unto the house of God at Jerusalem, in the second month, began Zerubbabel the son of Shealtiel, and Jeshua the son of Jozadak, and the remnant of their brethren the priests and the Levites, and all they that were come out of the captivity unto Jerusalem; and appointed the Levites, from twenty years old and upward, to oversee the work of the house of the LORD.
Numbers 4:3
From thirty years old and upward even until fifty years old, all that enter the service, to do the work in the tabernacle of meeting.
1 Chronicles 23:4
Of which, twenty and four thousand were to look after the work of the house of the LORD; and six thousand were officers and judges:
1 Chronicles 23:24-32
These were the sons of Levi by their fathers' houses; even the heads of their fathers' houses, as they were counted individually by the number of their names, that did the work for the service of the house of the LORD, from the age of twenty years and upward.
Ezra 4:3
But Zerubbabel, and Jeshua, and the rest of the heads of the fathers' houses of Israel, said unto them, You have nothing to do with us to build a house unto our God; but we ourselves together will build unto the LORD God of Israel, as king Cyrus the king of Persia has commanded us.