Judges 20:38-40

38Now the appointed signal between the men of Israel and the men in ambush was that they would make a great cloud of smoke rise up from the city,

39whereupon the men of Israel would turn in battle. Now Benjamin had begun to strike and kill about thirty of the men of Israel. For they said, “Surely they are defeated before us, as in the first battle.”

40But when the cloud began to rise from the city in a column of smoke, the Benjamites looked behind them, and there was the whole city going up in smoke to heaven.