The answer is: Joab

2 Sam 3:26-30 - Joab thought Abner was a spy

The deadly rivalry between Joab and Abner manifests in 2 Samuel, ultimately leading to a tragic twist. Joab, who was King David's fierce and loyal commander, held a personal vendetta against Abner, the general of Saul's army. A significant layer to this conflict lies in the brutal era of ancient Israel's civil war—scraps of trust and loyalty were easily torn apart in this power struggle.

The dramatic encounter highlights the depth of Joab's conflict; following the death of his brother Asahel at Abner's hands (2 Sam 2:23), Joab was consumed with revenge. While Abner approached David to negotiate peace and possibly unite the fractured kingdoms, Joab's swift and clandestine actions thwarted that hope. He even lured Abner back to Hebron under false pretenses—demonstrating the shrewdness often associated with military leaders during tumultuous times, but unfortunately, it led to a gruesome betrayal.

Interestingly, this tale echoes themes present throughout unstinting friendships and fierce rivalries—consider other key pairings like David and Saul, and how thematics weave through both love and revenge. Joab’s viciousness challenges the view of loyalty; even connections deemed unshakeable can be scattered in the face of ambition or grief. In this grim moment, the cycle of retribution is evident, foreshadowing that bloody arena where personal grievances frequently splatter the larger canvas of history. In these narratives, the nuanced portrayal prompts readers to contemplate the broader impact of personal conflict on communal destiny.