1 Chronicles 23:3

And the Levites, all those of thirty years old and over, were numbered; and the number of them, by heads, man by man, was thirty-eight thousand.

1 Chronicles 23:24

These were the sons of Levi, grouped by families, the heads of the families of those who were numbered by name, by heads, all those of twenty years old and over who did the work of the house of the Lord.

Numbers 4:2-49

Let the sons of Kohath, from among the sons of Levi, be numbered by their families, in the order of their fathers' houses;

Treasury of Scripture Knowledge

Summary

Now the Levites were numbered from the age of thirty years and upward: and their number by their polls, man by man, was thirty and eight thousand.

The levites

Thirty and eight

General references

Bible References

The levites

Numbers 4:2
Let the sons of Kohath, from among the sons of Levi, be numbered by their families, in the order of their fathers' houses;

Thirty and eight

Numbers 4:48
Came to eight thousand, five hundred and eighty.

General references

Numbers 4:35
Numbering all those from thirty to fifty years old who were able to do the work in the Tent of meeting;

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain