It would be easy to think that Samson was fearful for his life because of the three thousand men of Judah who came down to arrest him. But, I believe he was actually fearful for their lives! Note carefully what Samson made them promise - "Swear to me that you will not kill me yourselves" (Jud. 15:12). Why would Samson be afraid of the Israelites trying to kill him if he was not fearful of being turned over to the Philistines bound? I believe the answer is simple. Samson was not afraid of the Israelites, but he didn't want to end up hurting them if they attempted to kill him. Samson allowed them to arrest him and deliver him to the Philistines bound in two new ropes.
"When he came to Lehi, the Philistines came shouting against him. Then the Spirit of the LORD came mightily upon him; and the ropes that were on his arms became like flax that is burned with fire, and his bonds broke loose from his hands. He found a fresh jawbone of a donkey, reached out his hand and took it, and killed a thousand men with it" (Jud. 15:14,15). With the Lord's help, Samson piled up heaps of dead bodies on the battle field. He was invincible as long as Almighty God was with him! What a sight it would have been to see one man take on an army--with hand-to-hand combat--and win! How could this not inspire his fellow Israelites to fight alongside of him and overthrow the Philistines?
The chapter closes with Samson acknowledging Jehovah as his strength and the true victor. He then requested water and was divinely given such. We also learn that Samson judged Israel for a span of twenty years. These events happened somewhere amidst those years.
Samson's lust is apparent in this context. First, he had sexual relations with a harlot. Some of his enemies learned that he was spending the night with her, and they planned to kill him at daylight. However, he rose at midnight and left the city by pulling up the doors of a city gate and its gateposts and by carrying them some distance. Although commentators disagree on the distance, most believe it was at least several miles and up a hill. Although the size and weight of the load he was carrying is unknown today, it is obvious that the task required extreme strength that the Holy Spirit gave to Samson at that time.