Judges 20:38 in the King James Version
Now there was an appointed sign between the men of Israel and the liers in wait, that they should make a great flame with smoke rise up out of the city.
Context
37 The ambushers hurried, and rushed on Gibeah; then the ambushers spread out, and struck all the city with the edge of the sword.
38 Now the appointed sign between the men of Israel and the ambushers was that they should make a great cloud of smoke rise up out of the city.
39 The men of Israel turned in the battle, and Benjamin began to strike and kill of the men of Israel about thirty persons; for they said, “Surely they are struck down before us, as in the first battle.”