Judges 16:6-9

So Delilah said to Samson, “Please tell me what makes you so strong and what it would take to tie you up securely.” Samson replied, “If I were tied up with seven new bowstrings that have not yet been dried, I would become as weak as anyone else.” So the Philistine rulers brought Delilah seven new bowstrings, and she tied Samson up with them. She had hidden some men in one of the inner rooms of her house, and she cried out, “Samson! The Philistines have come to capture you!” But Samson snapped the bowstrings as a piece of string snaps when it is burned by a fire. So the secret of his strength was not discovered.