new purpose -- FIGHT THE ENEMY!

Ephesians 6:10-18 (New International Version)
"Finally, be strong in the Lord and in his mighty power.  Put on the full armor of God so that you can take your stand against the devil's schemes.  For our struggle is ... against the powers of this dark world and against the spiritual forces of evil in the heavenly realms.  Therefore put on the full armor of God, so ... you may be able to stand your ground, and after you have done everything, to stand.  Stand firm then, with the belt of truth buckled around your waist, with the breastplate of righteousness in place, and with your feet fitted with the readiness that comes from the gospel of peace...  take up the shield of faith, with which you can extinguish all the flaming arrows of the evil one.  Take the helmet of salvation and the sword of the Spirit, which is the word of God.  And pray in the Spirit (speaking in tongues) on all occasions with all kinds of prayers and requests. With this in mind, be alert and always keep on praying for all the saints. "

We've been given Spiritual Gifts and The Armor of God for defense.  

The helmet was a piece of armor that protected the Roman soldier against deadly blows to the head. What the helmet was to the Roman soldier, salvation is to the Christian soldier. There can be no victory unless the mind is protected with God’s Word. Romans 8:6 says, “For to be carnally minded is death; but to be spiritually minded is life and peace.” As Christians, the battlefield is in the area of our minds.  We must be careful to protect our minds from wrong thinking and be transformed by the renewing of our minds (Romans 12:2). Every thought can be brought captive to the obedience of Jesus Christ (2 Corinthians 10:4-5).

(Andrew Wommack's Living Commentary)

The “sword of the Spirit” is our only offensive weapon. In battle, defense is a great asset to any warrior.  This piece of armor has the ability to cut, wound, and hurt our Enemy, the devil. 

The Greek word used here is “RHEMA,” and it literally means a spoken word–specifically, a spoken word appropriate for your situation. It’s not the Bible lying on your coffee table that makes the Enemy flee; it is the Word of God hidden in your heart, activated by the power of the Holy Spirit, and spoken in an appropriate situation.  Jesus said in John 6:63–“The words that I speak unto you, they are spirit, and they are life.”  The words we speak that come from the written Word of God are empowered by the Holy Spirit. The Word by itself doesn’t make us free. It is the Word we know and speak that will deliver us (John 8:32).

The Word of God is effective because it has authority.  God’s Word supersedes all authority of the church, of reason, of intellect, and even of Satan himself.

The Holy Spirit wields this Word as it is spoken in faith.  Speaking God’s Word in faith brings the Holy Spirit into action. In Luke 4, when Jesus was tempted of the devil for forty days, it was “the sword of the Spirit,” the Word of God, that Jesus used to defeat the Enemy during His temptation.  Likewise, Christian soldiers must avail themselves of God’s Word by placing it in their hearts so that the Holy Spirit may bring it forth at the appropriate time to accomplish a complete and total victory.

(Andrew Wommack's Living Commentary)

A great resource on the significance of our Spiritual Armor is the book "Dressed to Kill" by Rick Renner.