In this chapter, Ahaziah king of Israel dies and Elijah kills a bunch of people with fire from heaven.
I have no idea how to write a summary for this chapter. How does one summarize the life of Elijah anyhow? This story of Elijah calling fire down from heaven is famous enough to be quoted in the New Testament, but there are a lot of other dynamics happening in this chapter that make it hard for me to say this chapter is about one particular thing.
So, let's begin. Moab rebels against the northern kingdom, Israel. Moab had been oppressed by Israel ever since the reign of David, who put two thirds of them to death in 2 Samuel 8:2. After the kingdom split, it appears that Moab remained subjected to the northern kingdom, but now after multiple defeats and internal strife, Israel is no longer able to control Moab. This is just another step in their long decline, but it's also just a footnote to this chapter as a whole.
Ahaziah falls through the lattice floor in the upper chamber. I don't know all of the details, but I think they constructed the floors by having two sets of intersecting wooden beams like a lattice, so there must have been a hole in the floor and Ahaziah fell through it and injured himself.
While Ahab wavered between following the LORD and following Baal, Ahaziah shows that he takes after his mother and sends immediately for Baal-zebub when he is injured to find out if he would recover. Although the text doesn't say it directly, I think part of the reason why Elijah declares that Ahaziah would die is because of Ahaziah's apparent idolatry in this chapter.
In 1 Kings 18, Elijah gets into a conflict with the prophets of Baal; Elijah challenges the people to cease wavering between two opinions and to either follow the LORD or follow Baal. In this chapter, we see another conflict but this time it is between Elijah and the king himself, Ahaziah. This is the second piece of evidence we have that Ahaziah represents a hardening of the idolatry against the influence of Elijah and the LORD. Ahab certainly had a lot of conflict with Elijah, at one time calling him a "troubler of Israel" and another time calling him "my enemy". But for reasons that I don't fully understand, Elijah maintained contact with Ahab and continued to influence him almost until the end of his life when Ahab finally, at last, repented for some of the evil he did (1 Kings 21:27-29). In a sense, I think that vindicated Elijah because it showed at the very end that Ahab, who wavered for so long, took at least one small step back towards the LORD, even though Ahab later treated Micaiah (another prophet of the LORD) very poorly. We do not have evidence that Ahab became a good person even after he repented, but for an least a moment he seemed to accept the dark condition of his own heart.
On the other hand, Ahaziah seems to be committed to serving Baal and sends for Baal immediately after getting injured. When Elijah interdicts his messenger and challenges Ahaziah, Ahaziah responds with the forcefulness that Ahab never had and tries to take him captive by force. In that sense, Ahaziah is acting more like a king than Ahab did, but unfortunately for Ahaziah, he is directing that force against the LORD who is not his subject. Unless Ahaziah repents, the conclusion to this conflict will be disastrous for him.
Another parallel between this chapter and 1 Kings 18 is the "fire from heaven". In 1 Kings 18, the fire was directed against the sacrifice and it was a sign of God's acceptance of Elijah and Elijah's authority. In this chapter, the fire falls upon Ahaziah's men, killing them. Once again this shows the major escalation in the conflict between the the kings of Israel and their God, since the fire of God is now falling on the kings' men to kill them.
Ahaziah sends three groups of soldiers. Even after the first two groups of soldiers were killed by fire from heaven, Ahaziah's response is unflinching: he would send another group. It is not Ahaziah, but the captain himself, who demonstrates humility towards Elijah and hence defuses the situation. I can only imagine how long Ahaziah would have kept sending groups of soldiers to their deaths. Even though Ahaziah is himself dying from his injury, he seeks to overpower Elijah rather than submit to God.
On the other hand, if Elijah had gone with the first group of soldiers, what would Ahaziah have done with him? Perhaps Elijah would have been thrown in prison or executed. You do not send a group of 50 soldiers to bring your friend over for a party at your house, this was clearly meant to intimidate Elijah and force him to come and perhaps reverse what he had declared over Ahaziah. Instead, it is the soldiers who are intimidated and that may be why Elijah was permitted to leave.
In the end, Ahaziah does not repent and he dies. His heart was hardened towards God and he refused to bow.
I began this chapter by noting the long and gradual decline of Israel as Moab rebelled against them. This chapter ends with the long and gradual moral decline of Israel as we can observe the wavering of Ahab turn into the hardened rebellion and hostility of Ahaziah. Ahab was certainly hostile to Elijah on several occasions, but Elijah continued reaching out to Ahab who eventually repented (in part) for what he had done wrong. Ahaziah does not repent and Elijah doesn't play any games with him. This increasing tension between the prophets of God and the kings of Israel is a bad omen, perhaps even worse than Israel's political setbacks, because power and authority flow from the LORD and it was David's relationship with God that strengthened him to conquer Moab in the first place.
Things are going to get worse in Israel before they get better.