Judges 16:8-9

8So the Philistine rulers gave Delilah seven new strings for bows. She used them to tie Samson up while he was asleep.

9Some Philistine men hid in a room of her house. Then she shouted, ‘Samson, the Philistines are here!’ But he broke the seven strings very easily. They were like thin cotton that a fire burns. So they did not discover the secret about his strength.