I’ve already mentioned that the Roman soldier had two kinds of shields. One was a small round shield that was carried into hand to hand combat. It was a lighter, thinner shield that could be maneuvered easily in battle. The other one, the one Paul talks about in Ephesians 6:16 is a large door shaped shield. That word for this shield is actually the same word that’s translated as door in English. It was about five feet high and two feet wide. It could cover a hunkered body completely. When soldiers carrying this “thura” advanced in lines together, the enemy was presented with what appeared to be a solid wall of shields and there would be row upon row of them as well. These advancing columns of the Roman army were called “phalanxes.” They were well known by the enemy and highly feared. When discussing this, Boice writes, “Paul is saying that our faith should be like that. It should do three things: (1) it should cover us so that not a portion is exposed, (2) it should link up with the faith of others to present a solid wall of defense, and (3) because it covers our entire person and links up with the faith of our fellow soldiers, it should be able to strike down whatever fiery arrows the enemy hurls at us.”

You will notice that Paul speaks of the shield of “faith.” Not the shield of “the faith” which would imply a set of truths that we believe in. No, instead, it’s means a general confidence in God and a strong conviction in the reliability and trustworthiness of God and His promises. So, Barnhouse concludes, “What is Faith? It is just believing God. If we believe Him, nothing can move us. Only when we allow our faith to be deceived, does our love grow cold; and we become an open target for Satan’s missiles. When we believe God, nothing can deceive us. No matter what attack is launched against us, if we believe God; the enemy’s efforts are harmless. ‘Let God be true, but every man a liar,’ said Paul (Rom. 3:4). When we take this attitude, we are invulnerable. If we love Him, we KNOW: and if we KNOW, the shield of faith will deflect every attack.”

Faith is not just a defensive shield. It’s one of the most powerful offensive weapons in God’s arsenal. The writer of the book of Hebrews teaches us how important faith is. Chapter 11 begins with, “Now faith is the assurance of things hoped for, the conviction of things not seen. For by it the people of old received their commendation. By faith we understand that the universe was created by the word of God, so that what is seen was not made out of things that are visible. By faith Abel…” It goes on to say “by faith…” and names all the heroes of the faith who trusted God while being attacked by the fiery darts of the evil one and prevailed. Faith is the substance! Paul tells us in the opening verses of Romans that he’s not ashamed of the good news of Jesus because it is the power of God to everyone who believes….” It is by God’s grace through faith… Faith is the substance!