About Ahithophel .
Ahitophel was King David's trusted advisor, and Bathsheba's grandfather
Why did Ahithophel betray David after so many years faithful service?
Ahithophel had been King David’s faithful counsellor for many decades, giving David the benefit of his great wisdom which was so brilliant, it was as if a man had inquired the Word of God (2 Samuel 16:23). When David learned his trusted friend had betrayed him, he was so afraid, he prayed, “O Lord I pray You, turn Ahithophel’s counsel into foolishness” (2 Samuel 15:31).
Bathsheba's father Eliam (2 Samuel 11:3), was the son of Ahithophel (2 Samuel 23:34); therefore Ahithophel was Bathsheba’s grandfather.