A calculated and cunning assassination unfolds under the guise of an innocent encounter, driven entirely by a personal desire for blood revenge. The tragic event begins with Joab pulling Abner aside into the gate. The primary approach among commentators is that Joab physically diverted Abner from the main road into the space of the city gate of Hebron. However, an alternative tradition suggests this was not merely a physical location but the gate of the elders. According to this view, Joab brought Abner before the high court of the Sanhedrin to face judgment for the killing of Asahel [רש״י, רד״ק, אלשיך, אברבנאל].
To ensure his trap worked, Joab employed careful deception. He spoke peacefully and pleasantly, ensuring that Abner approached in good faith and suspected nothing [רלב״ג, רד״ק, אברבנאל, שטיינזלץ]. Another perspective suggests Joab lured him by claiming King David had forgotten to share an important piece of information and had sent Joab to deliver the missing message [מלבי״ם, מצודת דוד, מצודת ציון]. Regardless of the exact method, the goal was to catch Abner completely off guard [רש״י, רד״ק, אברבנאל].
During this encounter, a tense legal discussion took place. Joab interrogated Abner about the death of his brother, Asahel. When Abner claimed he acted in self-defense against a pursuer, Joab challenged him, asking why he did not simply neutralize Asahel by striking one of his limbs. Abner replied that he was unable to aim with such precision. Joab immediately exposed the flaw in this defense, pointing out that Abner managed to strike Asahel precisely in the fifth rib, proving he had the skill to target a less vital area if he had chosen to. By cornering him with his own words, Joab established Abner's guilt [רד״ק, אלשיך, אברבנאל, שטיינזלץ].
Having proved his case, Joab needed an opportunity to strike. He cunningly posed a complex legal question: how does a woman without hands perform the ritual removal of a brother-in-law's shoe? Seeking to answer, Abner bent down to show that she would use her teeth. In that brief moment, with his body completely exposed and defenseless, Joab took advantage of the vulnerability and struck him [רד״ק, אלשיך, אברבנאל]. The fatal blow was delivered to the lower abdomen at the fifth rib, a highly sensitive area where the liver and gallbladder are located, ensuring a rapid death [מצודת דוד, שטיינזלץ]. Joab killed Abner in the exact same manner his brother had been killed, acting solely out of personal vengeance for Asahel's blood, without any connection to royal security or the king's interests [מלבי״ם, מצודת דוד].