Ezra 3:8
The second year and third month of their coming to the house of God in Jerusalem Zerubbabel, the son of Shealtiel, took charge of the construction. 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 the Levites, of twenty years or older, were responsible for overseeing the work of the house of Jehovah.
Numbers 4:3
Register all the men between the ages of thirty and fifty who are qualified to work at the tent of meeting.
1 Chronicles 23:4
David said: Of these, twenty-four thousand are to supervise the work of Jehovah's Temple and six thousand are to be officials and judges.
1 Chronicles 23:24-32
These were the descendants of Levi by their families, the heads of families as they were registered under their names and counted individually, that is, the workers twenty years old or more who served in the Temple of Jehovah.
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 will do the work for Jehovah, the God of Israel, as Cyrus, king of Persia, has given us orders.