Wiersbe's take on the situation was that Joab wanted a crown princess ready to take over if David died (David now being about 60 years old). The crown prince was currently exiled and couldn't come home without David's permission. But how could he just overlook the murder?
So Joab reasons with David via the wise woman deception.
Just a nerdy aside. It is interesting that when people wanted to see a change in David, they convinced him with stories. Howard Gardner is an American psychologist and education expert from Harvard. He is best known for his Multiple Intelligence theory. But he wrote a book on how to influence people and his research showed it to be stories.
We are still a tribal people. Only recently wearing suits and ties. We think we're far removed from our roots because of all of the modern blessing from God. But if you want to affect us, persuade us, change us...we respond to stories. It's odd. We might think logic would be the best. But people have knowledge in their head and are often unaffected by it. but if you put that same knowledge into a story, it can reach our inner most being and chance change. We've now seen it twice with David in just a few chapters.
He tried to passive the wise woman/actress, but she would not be put off. She persisted until she got him to say that he would spare her son's life. Now he was in the position that he would forgive a stranger; but leave his own son in exile. Now he had a reason to bring Absalom home.
Personally, I am a little annoyed that Amnon can rape without consequence and now Absalom can murder and run off to his other royal grandparents to wait it out. It feels like God's law doesn't apply to the royals. But the case being made here isn't. Absalom should go free because his your son. It's Israel is a newly renewed nation that's just now getting her feet underneath her after a long season of the judges. If you, David, die without a clear heir, all of Israel could lose her inheritance--the Promise Land.
Who gets forgiven and who pays full price? It's not up to us. We don't see the big picture. We don't see generational consequences and outcomes that the Lord sees clearly.
And besides, in actuality, like Michael Jackson or OJ Simpson, it may look like someone is getting away with evil because of who they are...but for both Amnon and Absalom, their reprieve was short lived. Neither prospered (or even lived) in the long run.
And in the end, because the Father was willing to sacrifice His Son and Jesus was willing to be tortured and slain, non of us get what we deserve. And we do get what we don't deserve. Grace and mercy. Praise God and may I never forget how much I have been forgiven.
David said Joab could go get Absalom, but when he was back, he had to stay on his own land (sort of a house arrest) and he couldn't visit the palace or see David.
Wiersbe points out that David and Absalom were reconciled, but there is no evidence that Absalom was repentant or that he paid the sacrifice he owed. So he came back to court privileges, but his heart was unchanged.
Wiersbe describes a little side plot that isn't obvious to me on first reading, so I don't know if it's theologically valid or just his opinion. But he describes how popular Absalom was and so when Absalom sent for Joab (twice) to come help him out of his house arrest situation, Joab didn't go because he didn't want to look like he was working for the prince at his beck and call.
So, Wiersbe writes that the reason Absalom had his servants set Joab's field on fire was to give Joab a reason to come see him- the arsonist would need to pay for the damages by law.
Final thought: that's a lot of palace intrigue, plotting, and scheming. And, in reality, despite Joab and Absalom's best efforts, Absalom never had a chance. He lived his life trying to become King. But he failed to ask the King Maker if that what he should do with his life. What if Joab and Absalom had been seeking the Lord' will during this time, instead of their own? Joab schemed to bring into Israel a man who would seek to destroy the King Joab was supposed to protect. When David asked why he had set up the whole theatrical scene with the "widow", Joab said "To change this present situation." Well, change he did. He put a traitor within arms reach of the king.
Here's the point, and it's meant for me, not just Joab and Absalom. God has a Will. And it will be done. We can either seek Him and do our best to be in His Will, or we can run around, plotting, scheming, burning down the days we've been given, and losing out on the blessing our loving Father had for us.