Soon after Joab and David's men came back from a raid, bringing with them a large amount of plunder. However, Abner wasn't there with David in Hebron because David had already sent him safely on his way in peace.
Joab went to the king and asked, “What do you think you're doing? Here's Abner, who came to see you. Why on earth did you send him on his way? Now he's got clean away!