Absalom had claimed the kingdom; but to keep the kingdom he would need to hunt down and kill the real king, David. So he consulted with his two counselors, Ahithophel and Hushai, who was David's spy.
When someone first told David of Ahithophel's betrayal and alliance with Absalom David prayer that God would turn Ahithophel's counsel into foolishness. God answered that prayer.
Ahithophel's plan was good and he made himself the center of it. He would ride out at night, quickly while David was running and weary and murder him, bringing back David's followers and uniting the kingdom. Now that's a man with big plans and a big future for himself. But as wise as he was; he forgot the main thing in any plan-include God. Ahithophel's plan, as wise and "correct" as it was for meeting Absalom and his own goal, it didn't account for God's plan.
Hushai painted an elaborate portrait that Absalom couldn't resist. Absalom should bring all Israel together into a massive force, and he should lead it. He should spread out and attack all of David's men, leave no unloyal followers to come back to Jerusalem. If David's men got to a city, take it apart stone by stone. Magnificent. Mighty. Victory. You can just see Hushai working Absalom into a frenzy, forgetting that he had no military expertise or practical ability experience to execute this plan.
Once again, people strongly persuaded, even against their own interest...bu a story. Painted by a master storyteller.
Hushai sets the spy ring in motion to get the word to David. It reads like George Washington's spy ring in the US Revolutionary War. It would make a great movie. Wiersbe points out the parallel to the spies on the run in Joshua 2.
As to why Ahithophel hanged himself, Wiersbe has a simple explanation- Ahithopel was wise and did have tremendous understanding of the situation. Once he knew that his correct and wise advise had not been taken, he knew that he had backed the wrong king. He knew Absalom would fail and that would leave him a traitor in the old kingdom, not a ruler in the new one. Rather than all the shame and drama for his family, he put his affairs in order and took himself out.
We cannot ever think that that we have arrived in our faith. Sometimes smart people allow their intelligence to cause them to trust in their own thinking. He knew how wise he was. And once his need for vengeance against David become his goal, rather than serving the Lord, he lost his way. Since he was still smart, he still assumed everything he thought and did was wise. But his intelligence was a gift from God, and never his own. While it looked like it was still serving him and getting him the results he wanted...God had the final say.
Very, very convicting. They aren't our gifts. They are his gifts on loan to us to do His Good Will. When we try to use them outside of His will, it may look like things are going our way; but they won't. God's will will be done. With us helping or with us hanging from a tree.
Wiersbe points out several parallels between Ahithophel and Judas. He even has some references in the Psalms and the Gospel of John. I'll have to explore that another day. It looks interesting.
Also, Wiersbe point about Ahithophel was about ending well. Which is where I started to go above, but was inspired by God with what actually came out. So, I'd like to explore the idea of ending well, but for another day.
There is a rich vein of learning in this chapter!
The last section of the chapter is back to David's parallel experience. He hears from the spies and mobilizes his entourage to cross the Jordan. they arrive Mahanaim, the former capital of the 10 tribes when Saul's son was "king". Also where Jacob saw the army of angels to protect him.
David had friends bring provisions, and literally, God prepared a table for David as his enemies were approaching! (Psalm 23:5)
This was a full civil war. Absalom chose David's nephew (and Joab's cousin) as his military commander and made himself commander in chief (with no experience). So family against family all the way around.