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

[228] But Ahithophel, on rejection of his advice, got upon his ass, and rode away to his own country, Gilon; and, calling his family together, he told them distinctly what advice he had given Absalom; and since he had not been persuaded by it, he said he would evidently perish, and this in no long time, and that David would overcome him, and return to his kingdom again; so he said it was better that he should take his own life away with freedom and magnanimity, than expose himself to be punished by David, in opposition to whom he had acted entirely for Absalom. When he had discoursed thus to them, he went into the inmost room of his house, and hanged himself; and thus was the death of Ahithophel, who was self-condemned; and when his relations had taken him down from the halter, they took care of his funeral. Now, as for David, he passed over Jordan, as we have said already, and came to Mahanaim, every fine and very strong city; and all the chief men of the country received him with great pleasure, both out of the shame they had that he should be forced to flee away [from Jerusalem], and out of the respect they bare him while he was in his former prosperity. These were Barzillai the Gileadite, and Siphar the ruler among the Ammonites, and Machir the principal man of Gilead; and these furnished him with plentiful provisions for himself and his followers, insomuch that they wanted no beds nor blankets for them, nor loaves of bread, nor wine; nay, they brought them a great many cattle for slaughter, and afforded them what furniture they wanted for their refreshment when they were weary, and for food, with plenty of other necessaries.