2 Samuel 16:21

Taking possession of the harem was the most decided act of sovereignty (see 1 Kings 2:22). It was also the greatest offence and insult that could be offered. Such an act on Absalom’s part made reconciliation impossible. A further motive has been found in this advice, namely, the desire on the part of Ahithophel to make David taste the bitterness of that cup which he had caused others (Uriah and all Bath-sheba’s family) to drink, and receive the measure which he had meted withal.