Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[211] But when Absalom, and Ahithophel his counselor, were come to Jerusalem, with all the people, David's friend, Hushai, came to them; and when he had worshipped Absalom, he withal wished that his kingdom might last a long time, and continue for all ages. But when Absalom said to him, "How comes this, that he who was so intimate a friend of my father's, and appeared faithful to him in all things, is not with him now, but hath left him, and is come over to me?" Hushai's answer was very pertinent and prudent; for he said, "We ought to follow God and the multitude of the people; while these, therefore, my lord and master, are with thee, it is fit that I should follow them, for thou hast received the kingdom from God. I will therefore, if thou believest me to be thy friend, show the same fidelity and kindness to thee, which thou knowest I have shown to thy father; nor is there any reason to be in the least dissatisfied with the present state of affairs, for the kingdom is not transferred into another, but remains still in the same family, by the son's receiving it after his father." This speech persuaded Absalom, who before suspected Hushai. And now he called Ahithophel, and consulted with him what he ought to do: he persuaded him to go in unto his father's concubines; for he said that "by this action the people would believe that thy difference with thy father is irreconcilable, and will thence fight with great alacrity against thy father, for hitherto they are afraid of taking up open enmity against him, out of an expectation that you will be reconciled again." Accordingly, Absalom was prevailed on by this advice, and commanded his servants to pitch him a tent upon the top of the royal palace, in the sight of the multitude; and he went in and lay with his father's concubines. Now this came to pass according to the prediction of Nathan, when he prophesied and signified to him that his son would rise up in rebellion against him.