Ziba supports David but lies about Mephibosheth.
Shimei reviled and curses David as a bloodthirsty man. Abishai wants to kill him, but David has had enough of that, and of the sons of Zeruiah.
Absalom enters the city, and Ahithophel advises him to sleep with David's concubines, to harden the lines and strengthen morale.
Hushai's counsel defeats Ahithophel's. Through a nice bit of espionage this saves David, and Ahithophel kills himself. David is supplied by Ammon and Barzillai.
The armies meet and David's men win. Joan treats Absalom as a traitor, defying David's public orders to him. Runners with messages to David emphasize the mixed news this is for him. The kingdom is restored but his son is dead.
How this is about Jesus
Jesus reversed David's retreat with shame, entering the city triumphantly.
He is reviled and crucified and falsely accused by his countrymen outside the city, too.
He is supported by women of Israel and some connected with Gentiles (Luke 8:3).
He is wisdom from God, and His ill advised follower also kills himself (Judas).
He bore the curse of a traitor and hung from the tree, pierced by cruel men who thought they were doing God service by their cruelty.
It's hard to break the cycle of accusation and reviling. David tried, but snaps at Abishai. Old tensions resurface in trying times.
Politics often requires (or thinks it does) cruelty to direct opinion of the masses. See David's concubines.
Opportunists (Ziba) and naysayers (Shimei) and cruel men (Joab) come out of the woodwork in hard times.
There are times we must choose God's kingdom over our family's convenience or preference. We cannot side with the disobedient against God, even if they are in our own family.