Ezra 3:8
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 above, to see that the work of the house of the LORD went forward.
Numbers 4:3
all that were able to war - for to do the work in the tabernacle of witness:
1 Chronicles 23:4
Of which twenty four thousand were set to further the work of the house of the LORD. And six thousand were officers and judges.
1 Chronicles 23:24-32
These are the children of Levi in the households of their fathers the ancient heads, viewed and numbered by name and poll by poll from twenty year and above, to work in the service of the house of the LORD.
Ezra 4:3
But Zerubbabel and Jeshua and the other ancient fathers of Israel answered them, "It belongeth not to you, but to us to build the house unto our God: for we ourselves will build alone unto the LORD our God of Israel, as Cyrus the king of Persia hath commanded us."