The Apostle Paul spent a great amount of time in Ephesus and ministered to that church longer than anywhere else he traveled. It is in his letter to the Ephesians that we find the passage about the Armor of God.
"Therefore, put on the full ARMOR of God, so that when the day of evil comes, you may be able to stand your ground, and after you have done everything to stand".
Paul wrote in this letter about the spiritual battles we face as Christians. Scripture acknowledges the reality of demonic presence and forces. The Bible teaches that we do not fight against flesh and blood, but against the dark forces of this world. This passage in Ephesians affirms that God has not left us on our own. God equips us to resist the enemy and be protected in these circumstances.
The analogies Paul uses match what a Roman soldier would have worn, which would have been easily understood by Paul's original audience. Christians today can still envision the pieces of Armor worn and how they protect and help us fight. The pieces of the Armor of God include a belt, breastplate, shoes, shield, helmet, and sword. The Armor of God includes mostly defensive pieces, but the sword is the piece of the Armor of God which we can use in offense. It is God's Word that we can use to fight false teachings and come against wickedness.