Judges 16:9

16:9 They hid in the bedroom and then she said to him, “The Philistines are here, Samson!” He snapped the bowstrings as easily as a thread of yarn snaps when it is put close to fire. The secret of his strength was not discovered.

Judges 16:17

16:17 Finally he told her his secret. He said to her, “My hair has never been cut, for I have been dedicated to God from the time I was conceived. If my head were shaved, my strength would leave me; I would become weak, and be just like all other men.”