TSK · Numbers 1:47

from twenty years old and upward, all who are able to go out to war in Israel. You and Aaron shall number them by their divisions.

But the Levites were not numbered among the children of Israel; as Yahweh commanded Moses.

Yahweh spoke to Moses, saying,

Those who were numbered of them were twenty-three thousand, every male from a month old and upward: for they were not numbered among the children of Israel, because there was no inheritance given them among the children of Israel.

But he didn't count Levi and Benjamin among them; for the king's word was abominable to Joab.