The Lord discomfited Sisera, with great terror and noise, as the word signifies, Exodus 14:24 Joshua 10:10 1Sa 10, most probably with thunder, and lightning, and hailstones, or other such instruments of destruction poured upon them from heaven, as is sufficiently implied, Judges 5:20. With the edge of the sword, i.e. by the sword of Barak and his army, whose ministry God used; but so that they had little else to do but to kill these whom God by more powerful arms had put to flight. Fled away on his feet, that he might flee away more secretly and securely in the quality of a common soldier, whereas his chariot would have exposed him to more observation and hazard.
Related Commentaries of Judges 4:15
Judges 4:15
15 And the LORD discomfited Sisera, and all his chariots, and all his host, with the edge of the sword before Barak; so that Sisera lighted down off his chariot, and fled away on his feet.