Ben Hadad sent a messenger to Achav who tells him that If Achav does not want to fight war then he has to give Ben Hadad all his money, his wife, and children. Achav does not want war so he says okay no problem, we are now your servants.
But when Ben Hadad changes his mind to everything that "He finds good in his eyes" meaning like the sefer Torah Achav does not know what to do.
The two kings go to war. A Navi told Achav that he will win so he will see the greatness of Hashem. And 7,000 people should be led by the 232 geirim. Why the Geirim? Hashem wanted to show everyone that they were not so great. He wanted the war to be won by good people.
Ben Hadad tells his servants that their g-d is a g-d of mountains and that is why they won. So he says that they should fight on flat land. They also chose captains instead of the king to lead the war because they thought the captains will try their best to show how good they were.
They fought in Afek. Already when the war just started 100 people had died. The rest went to a city and all the walls fell over and killed 27,000 people. Ben Hadad ran away. Ben Hadads servants say to go to Achav because he is a kind king. and ask him for help. When they went Achav reacted very excitedly "What?!?! Ben Hadad he is like my brother!"
They made a covenant that He will give him taxes off, give him back cities, and have a store. The problem with this was that Michayahu had told Achav to kill Ben Hadad. Michayahu criticized Achav for not killing Ben Hadad. Michayahu then told Achav he will have future destruction achav goes to Shomron upset.