Numbers 1:3

1:3 You and Aaron are to number all in Israel who can serve in the army, those who are twenty years old or older, by their divisions.

Numbers 1:45

1:45 All the Israelites who were twenty years old or older, who could serve in Israel’s army, were numbered according to their families.

Numbers 26:2

26:2 “Take a census of the whole community of Israelites, from twenty years old and upward, by their clans, everyone who can serve in the army of Israel.”

Numbers 31:14

The Death of the Midianite Women

31:14 But Moses was furious with the officers of the army, the commanders over thousands and commanders over hundreds, who had come from service in the war.

Numbers 31:48

31:48 Then the officers who were over the thousands of the army, the commanders over thousands and the commanders over hundreds, approached Moses