1 Chronicles 20:1

20:1 In the spring, at the time when kings normally conduct wars, Joab led the army into battle and devastated the land of the Ammonites. He went and besieged Rabbah, while David stayed in Jerusalem. Joab defeated Rabbah and tore it down.

1 Chronicles 27:1

Leaders of the Army

27:1 What follows is a list of Israelite family leaders and commanders of units of a thousand and a hundred, as well as their officers who served the king in various matters. Each division was assigned to serve for one month during the year; each consisted of 24,000 men.