1 Chronicles 23:24

from thirty years and upward, even to fifty years old, all who enter the duty of doing the work in the tent of meeting.

from thirty years and upward to fifty years old, you shall number them; all who enter to perform the duty of performing the service in the tent of meeting.

from thirty years and upward even to fifty years old, everyone who entered the duty of service in the tent of meeting.

“This is what applies to the Levites: from twenty-five years old and upward they shall enter to perform their duty in the service of the tent of meeting.

And the Levites were numbered from thirty years old and upward, and their number by census of men was 38,000.

as well as the priests who were recorded genealogically according to their fathers’ households, and the Levites from twenty years old and upwards, by their responsibilities and their divisions.

Now in the second year of their coming to the house of God at Jerusalem in the second month, Zerubbabel the son of Shealtiel and Jeshua the son of Jozadak and the rest of their brothers the priests and the Levites, and all who came from the captivity to Jerusalem, began the work and appointed the Levites from twenty years and older to direct the work of the house of Yahweh.

The Service of the Levites