2 Samuel 18:1-2

1David assembled the army that was with him. He appointed leaders of thousands and leaders of hundreds.

2David then sent out the army – a third under the leadership of Joab, a third under the leadership of Joab’s brother Abishai son of Zeruiah, and a third under the leadership of Ittai the Gittite. The king said to the troops, “I too will indeed march out with you.”