Heading down the other side of the mountain, Ziba (Mephiboseth's servant who you might remember from earlier) catches up with David, bringing donkeys and food for the people to ride and eat.
David asks where Mephiboseth is, and Ziba tells him that he stayed behind in Jerusalem to side with Absalom, hoping he would help restore Saul's kingdom for him.
David says that everything that once belonged to Mephiboseth is now Ziba's, and Ziba pays obeisance to David.
Kicked When He's Down
As David passes through the city of Bahurim, a man from Saul's house named Shimei comes out and curses David, throwing stones at him, and claiming that God is punishing David for betraying Saul by giving his kingdom to Absalom.
Abishai (Joab's brother) tells David that they should kill this dude. But David says that Shimei might just be cursing him because God told him to.
He says, furthermore, that God might actually comfort or recompense David for the curses that Shimei is hurling at him—rather than actually making him be cursed.
Shimei follows along for a while, still cursing. Eventually, David reaches the Jordan, and cools off.
Concubine O' Mine
Meanwhile, back in Jerusalem, Hushai (David's secret spy) runs up to Absalom, praising him.
Absalom, concerned, asks him why he has betrayed David to join him.
Hushai says that he's merely choosing to follow the man Israel has chosen to follow, just as he did when Israel chose David.
Absalom asks his counselor, Ahithophel, what he should do, now, and Ahithophel tells him to sleep with the concubines his father has left behind in the palace—this will make Absalom all the more repulsive to David, and will also (somehow) strengthen Absalom's people.
So—since everyone considers Ahithophel to be almost infallible, like an "oracle of God"—Absalom does this, before all of Israel (thus fulfilling part of the prophecy Nathan had made against David).