Ahithophel

Ahithophel (meaning brother of folly or brother of impiety) was David's chief counselor, renowned throughout Israel for advice so reliable that it was as if a man had inquired at the oracle of God (2 Samuel 16:23). His defection to Absalom's rebellion was one of the most painful betrayals David experienced — reflected in the lament psalms that speak of a trusted friend lifting the heel against him (Psalm 41:9; 55:12–14). After joining Absalom in Jerusalem, Ahithophel gave two crucial pieces of counsel: that Absalom should publicly take his father's concubines (fulfilled the prophecy of Nathan in 2 Samuel 12:11–12), and that he himself should immediately lead a night pursuit with 12,000 men to catch David before he could regroup.

The second counsel was deliberately countered by David's agent Hushai, whose alternative advice Absalom followed instead. When Ahithophel saw that his counsel was not taken, he rode home, set his house in order, and hanged himself — the only suicide in the historical books apart from Saul's and Samson's. His death before the final battle meant he did not witness the defeat of the rebellion his defection had enabled. The parallel between Ahithophel and Judas — both trusted insiders whose betrayals led to their suicides — was noted by patristic commentators.