In this chapter, Samson is finally betrayed by his indiscretions and is captured by the Philistines.
This is something we should have seen coming for the last two chapters. Even in the midst of all Samson's sins, the Lord was still blessing him with great strength, and he used his power to fight in revenge of his own personal interests rather than advancing the interests of his countrymen.
Probably the best analogy to what happens here is the life of Adam. We are told that Adam sinned and was condemned to death in Genesis 3, but he nevertheless continued to live until he was 930 years old. So it took time for the consequences of his actions to catch up with him, but it eventually did.
In the same way, Judges 16 is the inevitable day of reckoning for Samson when his mistakes catch up with him, and it's basically the same issue; sexual desire for Philistine women.
This story has always confused me a little. I guess what I don't understand is why Samson keeps going back to Delilah. From the story, we can infer that he slept with her for at least 4 nights, and he knew that on 3 separate occasions Delilah betrayed him by trying to bind him to remove his strength. It's not just that she keeps asking him how his strength may be "afflicted", but that she also does the things that he tells her. Why is Samson continuing to go back to Delilah when he knows that she's trying to harm him? That's what I don't understand. You'd think even with a selfish heart, Samson would realize she is trying to kill him.
In the end, Samson reveals that his strength came from his Nazirite dedication. Of course, we already knew this. But it's strange to me that his power is derived from his unshaved hair. It's true that this is one of the signs of the Nazirite, but I believe the Nazirite vow means so many other things, like obeying the whole law. The law that forbids intermarrying with Canaanites, which is what Samson has been doing all this time. Shaving his consecrated hair is really the last step of breaking his Nazirite vow, not the first.
The way this story is normally understood is that verse 19 is considered Samson's fall from grace, when the "LORD departed from him". Verse 22, when his hair starts to grow back, is an allusion to Samson's redemption. The conclusion, when "the dead whom [Samson] killed in his death were more than those whom he killed in his life", is meant to reflect his redemption and return to grace. In particular, we can tell that as his hair regrew, his strength also returned, and that was how he destroyed the temple where he was brought to entertain the Philistines.
So that is the story arc in how Samson is normally interpreted. And I think that's mostly true. However, I would like to point out how Samson is still motivated by personal revenge. Like he prays in v. 28, he wants revenge "for my two eyes". So I guess I don't really feel that Samson ever turned away from the selfishness that dictated his actions in life. But what is clear is that the LORD used him to harm the Philistines, to try to free Israel from their oppressors. What's not clear is if the Israelites were even freed. We know that Samson killed a bunch of people, but it doesn't say that Israel was liberated through this.
So here's my personal opinion on Samson. This conclusion to his life and his story is indeed a sort of redemption. The LORD slowly began to return his strength to him, and he used it in a final act of vengeance against the Philistines. I don't know if Samson's heart was ever turned back to his calling and destiny, or his Nazirite vow. And he did some good for his people, but only incidentally to his own desire for personal revenge. It's evident that Samson never really walked into his destiny, and it's not because he lacked power, it's because he lacked character. Even in Samson's redemption, he never really returned to do what he was born to do. That's my opinion.