Ezra 3:8
And 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 they who had come out of the captivity to Jerusalem, began. And they chose the Levites, from twenty years old and upward, to set forward the work of the house of Jehovah.
Numbers 4:3
from thirty years old and upward even to fifty years, all that enter into the service, to do the work in the tabernacle of the congregation.
1 Chronicles 23:4
Of these, twenty-four thousand were to set forward the work of the house of Jehovah, and six thousand officers and judges.
1 Chronicles 23:24-32
These were the sons of Levi after the house of their fathers, the chief of the fathers, as they were counted by number of names by their heads, the ones who did the work for the service of the house of Jehovah, from the age of twenty years and upward.
Ezra 4:3
But Zerubbabel, and Jeshua, and the rest of the chief of the fathers of Israel, said to them, You have nothing to do with us to build a house to our God. But we ourselves together will build to Jehovah, the God of Israel, as King Cyrus the king of Persia has commanded us.