And take the helmet of salvation, and the sword of the Spirit, which is the word of God:
Several preachers have mentioned that the Sword of the Spirit is the only offensive weapon in this armor. This implies that we can use God's Word to ward off the attacks of the devil. We can use it to defeat the enemy.
"For the word of God is quick, and powerful, and sharper than any twoedged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart." (Hebrews 4:10)
So far, no effort of man or his logic is even mentioned in the armor of the Spirit. It is all spiritual armor - that takes man's choice to put on and keep on. We know that God's Word is our Sword, but do we sharpen it in our lives? Do we read it, study it, and apply it? The Sword does not offer much protection if it is rusted in its sheath. It has to be brought out and practiced with for us to know how to use it. If we do not use God's Word in the small areas of our life, how will we be able to use it when it comes to the darkness of spiritual warfare?
For a further study of the power, might, majesty, and ability of God's Word, Psalm 119 has the most to say about God's Word. If one doubts its ability to guide, direct, fight, keep, and help, they should read Psalm 119.