Jerubbesheth, called also Jerubbaal, Judges 9:1. See Poole on "2 Samuel 2:8". Thy servant Uriah the Hittite is dead also; which he knew would be acceptable news to the king, and therefore allay his wrath. This indeed might make the messenger suspect that David had a hand in Uriah's death; and possibly Joab might say so for that very reason, that these matters by degrees being known, David might be hardened in sin, and so Joab might have the greater interest in him.
Related Commentaries of 2 Samuel 11:21
2 Samuel 11:21
21 Who smote Abimelech the son of Jerubbesheth? did not a woman cast a piece of a millstone upon him from the wall, that he died in Thebez? why went ye nigh the wall? then say thou, Thy servant Uriah the Hittite is dead also.