Judges 15:14
And when he came unto Lehi, the Philistines shouted against him: and the Spirit of the LORD came mightily upon him, and the cords that were upon his arms became as flax that was burnt with fire, and his bands loosed from off his hands. And when he came unto Lehi, the Philistines shouted against him: and the Spirit of the LORD came mightily upon him, and the cords that were upon his arms became as flax that was burnt with fire, and his bands loosed from off his hands.
Samson allowed his own countrymen to deliver him to the Philistines because he would not harm men of Judah, and after three thousand men of Judah came to him at the rock Etam he first made them promise not to attack him themselves, then let them bind him with two new ropes and lead him into the Philistine camp amid shouts of joy echoing from the hills. When the Philistines shouted against him, the Spirit of Jehovah came mightily upon him with supernatural strength, and the strong new cords upon his arms became like flax burned in fire and loosed from off his hands, freeing him. With his hands thus freed, he seized the jawbone of an ass and smote the Philistines.
His extraordinary strength came from God and not from his physical build alone. His unshorn hair symbolized his Nazarite condition, on which his strength depended. The coming of the Spirit of God upon him in that moment is like the coming of the Spirit upon Saul when Saul was roused to act as hero and king.
His victory could have freed Israel from the power of its oppressors if the Israelites had been ready to unite with him and follow it up. They failed to do so because they had become dispirited and cowardly, having neglected God's command to dispossess the heathen, having united with them in degrading practices, having tolerated their cruelty and even countenanced their injustice so long as it was not directed against themselves, and when themselves brought under the oppressor's power tamely submitting to a degradation they might have escaped by obeying God. Their course shows their repeated pattern of deserting the deliverer the Lord raised up for them and uniting with their enemies. He had the choice to rely on God's strength and resist temptation, but instead he let his passions rule him.