Theodoret of Cyrus
What is the significance of the declaration, ‘Go in this thy fortress, and thou shalt save Israel from the hand of Midian’ (Judges 6:14)? Gideon, encouraged by the angel to assemble forces and confront the enemy, responded, ‘And if the Lord be with us, why have we found all these evils? And where are all His miracles, which our fathers told us, saying, “The Lord brought us out of Egypt?” And now the Lord hath cast us off, and delivered us into the hand of Midian’ (Judges 6:13). Thus, since Gideon recalled God's mighty deeds and had developed a strong belief that if God willed it, He could easily rescue the Israelites from their afflictions, the angel instructed him to go in his strength, assuring him that with such faith, he would prevail against Midian.