Like with all the other enemies of David, things really fall apart for Saul's son, Ishbaal. I won't spoil anything but he dies and David becomes king of the entire land of Israel and Judah.
We start really getting into 1 Chronicles and talk about where the book came from and the differences with the books of Samuel and Kings.
We find out that David really can't stand the blind and lame. Therefore, he wants his people to attack the Jebusites by climbing up a well. That's the kind of reasoning the bible contains.
David gets jiggy wit it big Willie style.