What does Judges 7:20 mean?
Gideon's attack against the Midianites (Judges 7:9) has begun. His three groups of one hundred men each have taken their places around the perimeter of the enemy camp. Gideon and his group blew loudly on their ram's horn trumpets and smashed their clay pitchers. Hearing the noise, the other two groups now immediately do the same thing (Judges 7:15–18).The smashing of the clay jars not only added a loud, unexpected noise, it also exposed the reed-style torches inside them to the air, causing the flames to burn bright. Gideon and each of his 300 soldiers held their torches high with their left hands and continued to hold their trumpets with their right hands. They also kept shouting out, "A sword for the Lord and for Gideon!"
Of course, the sword of the Lord against the Midianites did not include any swords. In fact, the Israelites did not "attack" with any weapons other than noise and light and the confusion they produced in the Midianite camp. That confusion would have been considerable. The presence of so many torches and trumpets would have given the appearance of a much-larger army. Further, Israel is attacking while most of the enemy are asleep, and armed guards are just returning from their watch (Judges 7:19). In the chaos and confusion, some of those returning Midianites were likely mistaken for enemy invaders, and attacked, starting a chain reaction of absolute mayhem (Judges 7:21–23).