The answer is: Joab

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

In the context of 2 Samuel, the relationship between Joab and Abner is steeped in tension and rivalry. Joab, the commander of David's armies, possessed a fierce loyalty to King David but became blinded by vengeance and suspicions toward Abner, who was once the rival general leading Saul's forces. Joab's decision to eliminate Abner is seen not just as an act of wartime betrayal but as a brutal assertion of power within the shifting dynamics of Israel's leadership. It’s a classic tale of how paranoia can fuel violent actions—Joab believed Abner was a threat and acted decisively, fueling an uncovering of morality in the quest for authority.

Interestingly, earlier in the Bible, David had expressed a more sympathetic view of loyalty and reconciliation. In 2 Samuel 1, upon learning of Saul's and Jonathan's deaths, David grieves profoundly—he shows respect for their former rulers, whereas Joab's heart remains hardened against those he views as rivals. This dichotomy highlights the varying responses to the complex historical ebbs and flows that characterized ancient Israel.

In biblical tradition, Joab’s actions may echo the cycles of vengeance and loyalty disputes prominent in other sections of scripture, raising questions about the burden of leadership and the potential for misjudgment in one's pursuit for safety and power. The story serves as a sober reminder about the consequences that can arise when the balance of justice tips toward vengeance.