Ezra 3:8

Now, in the second year of their coming in unto the house of God, to Jerusalem, in the second month, began Zerubbabel son of Shealtiel and Jeshua son of Jozadak and the rest of their brethren - the priests and the Levites, and all that were come out of the captivity to Jerusalem, and stationed the Levites, of twenty years old and upwards, to preside over the work of the house of Yahweh.

Numbers 4:3

from thirty years old, and upwards, even unto fifty years, - every one that can enter into the host, to do service in the tent of meeting.

1 Chronicles 23:4

Of these - to preside over the work of the house of Yahweh, were twenty-four thousand, - and officers and judges, six thousand;

1 Chronicles 23:24-32

These, were the sons of Levi by their ancestral house, the ancestral chiefs of them who were counted in the number of their names, by their polls, doing the work, for the service of the house of Yahweh, - from twenty years old, and upwards.

Ezra 4:3

But Zerubbabel and Joshua and the rest of the ancestral chiefs of Israel, said unto them, It pertaineth not to you and to us in common , to build a house unto our God, - but, we ourselves together, will build unto Yahweh, God of Israel, even as King Cyrus, king of Persia, hath commanded us.

Treasury of Scripture Knowledge

Summary

Now 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 upward, to set forward the work of the house of the LORD.

Twenty years old

Bible References

Twenty years old

Numbers 4:3
from thirty years old, and upwards, even unto fifty years, - every one that can enter into the host, to do service in the tent of meeting.
1 Chronicles 23:24
These, were the sons of Levi by their ancestral house, the ancestral chiefs of them who were counted in the number of their names, by their polls, doing the work, for the service of the house of Yahweh, - from twenty years old, and upwards.