Ezra 3:8
In the second year after their coming to the house of God at Jerusalem, in the second month, Zerubbabel son of Shealtiel and Jeshua son of Jehozadak began [their work], and the remainder of their brothers the priests and the Levites and all who came from the captivity to Jerusalem. They appointed the Levites {from twenty years and older} to direct the work of the house of Yahweh.
Numbers 4:3
from {thirty years old} and above, up to {fifty years old}, everyone who comes to the service to do the work in the tent of assembly.
1 Chronicles 23:4
Of these, [David said,] "Twenty-four thousand [are] to direct the work of the house of Yahweh, along with six thousand judges and officials
1 Chronicles 23:24-32
These [were] the sons of Levi according to the house of their fathers, the heads of the {families}, according to their enrollment, by the number of the names, according to their head count, [who were to] do the work of the service of the house of Yahweh, from twenty years old and above.
Ezra 4:3
But Zerubbabel, Jeshua, and the rest of the heads of the {families} of Israel said to them, "[It is] not for you but for us to build a house for our God. For we ourselves alone will build [it] for Yahweh the God of Israel, just as Cyrus the king of Persia has commanded us."