This famous picture sums up the Letter. The armor represents both a promise of divine protection and an exhortation to battle. Like a general encouraging his troops, Paul tells us that the victory is certain because Christ has already won the war, and He has made us well-prepared to stand with Him to face any last-ditch assaults. In ancient legends, the weapons and armor of a hero could give certain victory to anyone who wore them (cf. 1 Samuel 17:38). The armor Paul describes is not simply from God; it is God’s own armor, what He Himself wore in battle. Dressed in Christ’s armor, we look remarkably like Christ, for through baptism we are clothed with Him. (from the Lutheran Study Bible – CPH-2009)