While the men were hidden in her room, she called out, "Samson, the Philistines are here!" But he snapped the bowstrings like a strand of yarn seared by a flame. So the source of his strength remained unknown.

Judges 16:7
Samson told her, "If they tie me up with seven fresh bowstrings that have not been dried, I will become as weak as any other man."

Judges 16:8
So the lords of the Philistines brought her seven fresh bowstrings that had not been dried, and she tied him up with them.

Judges 16:10
Then Delilah said to Samson, "You have mocked me and lied to me! Now please tell me how you can be tied up."

Now there were men lying in wait, abiding with her in the chamber. And she said to him, The Philistines be on you, Samson. And he broke the thongs, as a thread of wick is broken when it touches the fire. So his strength was not known.