John Gill's Bible Commentary Ver. 7. And there went out after him Joab’s men , etc.] Who though he was removed from his post as general, yet might still have the command of a regiment: and the Cherethites, and the Pelethites ; over whom Benaiah was, ( Samuel 20:23); these attended David in his flight, and had now returned with him, ( 2 Samuel 15:18); and all the mighty men ; the military men that were at Jerusalem as many as could be spared: and they went out of Jerusalem to pursue after Sheba the son of Bichri ; with Abishai at the head of them; Josephus says there were six hundred, besides the soldiers at Jerusalem that went on this pursuit.
Matthew Henry Commentary
Verses 4-13 - Joab barbarously murdered Amasa. The more plot there is in a sin, the worse it is. Joab contentedly sacrificed the interest both of the kin and the kingdom to his personal revenge. But one would wonder with what face a murderer could pursue a traitor; and how, under such a load of guilt, he had courage to enter upon danger: his conscience was seared.
Original Hebrew ויצאו3318 אחריו310 אנשׁי376 יואב3097 והכרתי3774 והפלתי6432 וכל3605 הגברים1368 ויצאו3318 מירושׁלם3389 לרדף7291 אחרי310 שׁבע7652 בן1121 בכרי׃1075