1 Chronicles 23:3

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.

“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.

These were the sons of Levi according to their fathers’ households, even the heads of the fathers’ households of those of them who were counted, in the number of names by their census, doing the work for the service of the house of Yahweh, from twenty years old and upward.

without regard to their genealogical record, to the males from thirty years old and upward—everyone who entered the house of Yahweh for his daily obligations—for their service in their responsibilities according to their divisions;

The Work of the Levites