Judges 16:7-9

7And Samson said unto her, If they bind me with seven green withes that were never dried, then shall I become weak, and be as another man. 8Then the lords of the Philistines brought up to her seven green withes which had not been dried, and she bound him with them. 9Now she had liers-in-wait abiding in the inner chamber. And she said unto him, The Philistines are upon thee, Samson. And he brake the withes, as a string of tow is broken when it toucheth the fire. So his strength was not known.