But the spirit of the LORD clothed Gideon; and he blew a shofar; and Abiezer was gathered together after him. Judges 6:34
At first glance this verse seems to merely record how Gideon called up the troops, using the shofar like a bugle or another type of horn. But note that the summons to battle is juxtaposed with a profound spiritual change in Gideon. The classical commentators explain that Gideon was “enclothed” with a spirit of might and courage from G-d. Then he blows the shofar.
Note that he used the shofar to summon Aviezer, but to summon troops from elsewhere he sends messengers. The Aviezer clan was devoted, and apparently joined him instinctively upon hearing the call of the shofar.
The shofar appears again in Chapter 7. After Gideon pares down his troops to an elite fighting force of 300 shock troops, he equips each soldier with a shofar. These shofars were not intended merely as a tactical combat tool, but to gain spiritual advantage as well. As Rashi notes (Judges 7:13), they carried shofars and torches as reminders of the merit of the Giving of the Torah.
In From Dan to Megiddo, Rabbi Benjamin Fleischer writes that the Sages placed Gideon on a level with Moses and Samuel, and as a general, alongside Joshua and Barak. His brilliant tactic of using shofars and torches to confound the enemy transformed his soldiers “as if by magic, suddenly, in a super-natural manner into heroes and fearless fighters, revived by a spirit of celestial fire and zeal, with an awakening of higher national consciousness of their pure and Divine faith.”
From a practical military perspective, Gideon’s battle plan was based on a knowledge of the composition of the enormous Midian army, with its fierce cavalry 150,000 strong. He took into consideration the fact that the barbarian army was a heterogeneous amalgamations of various races and nations, with no unifed command and no uniformity of discipline or military conduct. Likewise they were unaquainted with the lingual customs of the various tribes and divisions that constituted the army.
When confronted by Israel’s surprise attack in the middle of the night, breaking into the center of the camp, general panic ensued. As their military order vanished, they fled like a terrified mob, trampling their own men and scattering in all directions.