Judges 20:38

Now there was an appointed sign between the men of Israel and the liers in wait,.... Or an appointed time z as the Targum; so Kimchi and Abarbinel. There was a time fixed, at which the men of Israel proposed to be at Baaltamar, exactly when the Benjaminites would be drawn at a proper distance from the city, and then the liers in wait were to break forth, and rush upon it, and enter it:

and that they should make a great flame with smoke to rise up out of the city; set it on fire, and cause the fire to burn fiercely, that there might be a large ascent of flame and smoke to be seen afar off; which, when the men of Israel saw, they would know the city was taken.

z המועד "tempus constitutum", Panginus, Montanus, Junius et Tremellius, Piscator.