Well let's try this again...I did the wrong passage so here is a quick post on the correct passages.
In 2 Samuel 3:13-15 we see an odd exchange. David demands Abner and Ish-Bosheth return Michal to him. Michal was one of Saul's daughters and given to David in return for 100 Philistine foreskins. When David fled Saul for the final time, Saul gave Michal to another man. We have a scene where her current husband follows the group weeping, before being told to leave them alone. That is the last we read of Paltiel of Laish. I'm not even sure where to go with that other than it must have looked weird to travelers passing the royal procession to present Michal to David and a weeping man following behind.
Joab strikes me as someone who does what needs to be done, not just because he is told but because he believes it to be the right thing to do. That is why he murders Abner, receiving a curse from David in the process. He then leads the attack on Jerusalem and is promoted to General of the David's armies. He also spearheads the rebuilding Jerusalem after the attacks. His story gets revealed in future passages but it includes disobeying David to kill who needed to be killed, and confronting and chastising that same king for not being a strong leader for their armies. *Spoiler alert, it doesn't end well.
At the conclusion of these passages, after many years running from Saul, and another 7 years in a civil war with Saul's son, David is crowned King of all Israel.