Ahithophel continues to give advice. He tells Absalom that he, Ahithophel, should be permitted to ride out with twelve thousand men. They will surprise David in the midst of his exhaustion, and kill him. With David dead, everyone else will come back, and join Absalom's new government.
Absalom and all his people think this sounds like pretty good advice.
But Absalom decides to get a second opinion from Hushai the Archite (actually, a spy for David).
Hushai doesn't think Ahithophel is giving very good advice (even though he probably is). He thinks that David isn't going to go down so easily—he and his men are valiant warriors, and they'll put up more of a fight than Ahithophel thinks.
What they should do, says Hushai, is launch a major battle campaign, with all of Israel gathered together to fight David.
Absalom decides that Hushai's advice is better—and the narrator chimes in, saying that God helped Hushai defeat the counsel of Ahithophel.
They Forget about the Well Every Time
Hushai tells the two pro-David priests, Zadok and Abiathar, what Absalom's plans are, and they send a servant-girl to tell him to keep going and not to camp at the fords overnight.
But when Zadok's sons, Ahimaaz and Jonathan, receive the message, a boy spies them and notifies Absalom.
Fleeing from Absalom's men, a couple in Bahurim, allow Ahimaaz and Jonathan to hide in a well in their backyard. When Absalom's searchers arrive, the couple tell them that Ahimaaz and Jonathan have already gone on ahead.
Ahimaaz and Jonathan successfully pass the message to David—and, in case Absalom ends up following Ahithophel's advice anyway, David heads onwards, successfully crossing the Jordan with all his people before dawn.
Back in Jerusalem, Ahithophel is so distraught over Absalom refusing his counsel that he returns home and hangs himself.
David and his people flee to the city of Mahanaim, while Absalom and his Israelites cross the Jordan, encamping in the land of Gilead. Absalom's chief general is a guy named Amasa, Joab's brother-in-law.
Arriving in Mahanaim, kindly people provide David and his supporters with an ample amount of supplies and food.