שמואל ב, פרק ג׳, פסוק ל׳

The narrative pauses its forward momentum to expose the hidden motives and true participants behind a shocking assassination. A stark moral contrast emerges between the tragic but accepted death of a warrior on the battlefield and a calculated political murder disguised as an act of revenge during a time of peace.

Although Joab physically struck the fatal blow against Abner, his brother Abishai is held equally responsible. Because Abishai walked into the city alongside Joab, sharing his intent and providing support, he is viewed as a full partner in the crime [רד״ק, מצודת דוד, מלבי״ם]. This shared guilt explains why King David's subsequent curse for the murder fell upon Joab's entire family [מלבי״ם]. The exposure of the brothers' true motive also corrects a misconception held by David. The king suspected that Joab killed Abner out of political jealousy, fearing Abner's new alliance and growing closeness to the throne. In reality, the brothers were driven purely by a desire for blood revenge over the death of their brother, Asahel [אברבנאל].

Even with this motive of revenge, the assassination was entirely unlawful. Abner had killed Asahel out of strict self-defense and a lack of alternatives while Asahel relentlessly pursued him in the heat of combat [ביאור שטיינזלץ]. A legal debate surrounds Joab's justification for the revenge. Joab argued that Abner could have merely wounded Asahel in a limb to stop the chase, rather than delivering a fatal blow [מלבי״ם, חומת אנך בשם כנה״ג]. Conversely, a counterargument states that in the chaos of war, it is unreasonable to expect a soldier to carefully aim for a non-lethal injury, meaning Abner acted completely within the bounds of the law [חומת אנך].

The primary approach among commentators is that the grave injustice committed by Joab and Abishai lies in the extreme difference in the situations: Abner took a life during active warfare, whereas the brothers committed cold-blooded murder during a time of peace. This tragic event carried heavy consequences, not only for the perpetrators but for King David himself. David was ultimately punished for cursing Joab too harshly and improperly, especially since he already planned to have Joab executed for the crime at a later time. Because of this excessive reaction, the severe curses David directed at Joab eventually rebounded onto his own descendants, afflicting the kings of Judah for generations to come [אברבנאל].