The Lord shall cause thine enemies that rise up against thee to be smitten before thy face: they shall come out against thee one way, and flee before thee seven ways. (Deuteronomy 28:7)
As their enemies advanced upon them in tight formation, rank upon rank of fighting men, as was the custom, they would be scattered as if they were an unorganized mob (see Judges 7:21, 22 on the Midianites, and 2 Kings 7:7 on the Syrians).