Now she had an ambush waiting in the inner room. And she said to him, “The Philistines are on you, Samson!” But he broke the bowstrings as a string of flax is broken when it smells fire. So his strength was not known. Bible other translations

“when it smells fire.” An idiomatic phrase, indicating that it got close enough to “smell” the fire.

Commentary for: Judges 16:9