King David’s trusted counselor who turned traitor and joined Absalom’s conspiracy. Ahithophel’s counsel was highly regarded, almost as though it were an oracle of God (2 Sm 16:23). On hearing about Ahithophel’s defection to Absalom, David prayed, "O Lord, I pray thee, turn the counsel of Ahithophel into foolishness" (2 Sm 15:31). Ahithophel advised Absalom to take over the royal harem (2 Sm 16:20-22). Taking possession of the harem was a public act declaring a former king to be deceased and replaced. Since David was still alive, the act was meant to bring about a final cleavage between David and Absalom. It also fulfilled Nathan’s prophecy to David that because David had taken another man’s wife in secret, his own wives would be taken from him in public (2 Sm 12:7-12).
Ahithophel’s second stratagem was to attack David quickly with 12,000 elite troops (2 Sm 17:1-3). Absalom rejected this advice, however, and accepted a countersuggestion by Hushai, David’s spy in Absalom’s palace. In a speech designed to inflate Absalom’s ego and gain time for David, Hushai advised a full campaign (2 Sm 17:4-14). When Ahithophel saw that his counsel was not followed, he went to his hometown and hanged himself (2 Sm 17:23).
Ahithophel is surely in David’s mind in Psalm 41:9, "Even my bosom friend in whom I trusted, who ate of my bread, has lifted his heel against me." In the NT the similarity of Judas to Ahithophel is seen by Jesus’ use of Psalm 41:9 to describe his own situation (Jn 13:18).
Elwell, W. A., & Beitzel, B. J. (1988). Baker encyclopedia of the Bible. Map on lining papers. (44). Grand Rapids, Mich.: Baker Book House.