Ezra 3:8
Now in the second year of their coming into the house of God in Jerusalem, in the second month, the work was taken in hand by 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 had come from the land where they were prisoners to Jerusalem: and they made the Levites, of twenty years old and over, responsible for overseeing the work of the house of the Lord.
Numbers 4:3
All those from thirty to fifty years old who are able to do the work of the Tent of meeting.
1 Chronicles 23:4
Of these, twenty-four thousand were to be overseers of the work of the house of the Lord, and six thousand were judges and men of authority
1 Chronicles 23:24-32
These were the sons of Levi, grouped by families, the heads of the families of those who were numbered by name, by heads, all those of twenty years old and over who did the work of the house of the Lord.
Ezra 4:3
But Zerubbabel and Jeshua and the rest of the heads of families in Israel said to them, You have no part with us in the building of a house for our God; we ourselves will do the work together for the Lord, the God of Israel, as Cyrus, king of Persia, has given us orders.