Finally, be strong in the Lord, and in the strength of his might. Put on the whole armor of God, that ye may be able to stand against the wiles of the devil. For our wrestling is not against flesh and blood, but against the principalities, against the powers, against the world-rulers of this darkness, against the spiritual hosts of wickedness in the heavenly places. Wherefore take up the whole armor of God, that ye may be able to withstand in the evil day, and, having done all, to stand. Stand therefore, having girded your loins with truth, and having put on the breastplate of righteousness, and having shod your feet with the preparation of the gospel of peace; withal taking up the shield of faith, wherewith ye shall be able to quench all the fiery darts of the evil one. And take the helmet of salvation, and the sword of the Spirit, which is the word of God: with all prayer and supplication praying at all seasons in the Spirit, and watching thereunto in all perseverance and supplication for all the saints.
Commentators have long analyzed this passage in light of the armor of the Roman soldier, which the apostle Paul evidently used as his model. Some get into the nitty gritty detail and historical minutiae of what this or that armor component looked like, what it did, how it related to the other pieces of the armor, etc. Other commentators focus on the area of the soldier's body each piece protected, seeking to draw spiritual applications from that. I don't discount either of these basic interpretations; I have found elements of most of them quite edifying. However, I'd like to offer an alternate meaning for the Armor’s components, one which may complement or enhance the standard interpretations in a very practical sense.
The premise: Spiritual attack takes place in the believer’s mind. These attacks often target the believer’s thinking about who he is and what he has in Christ. Because these attacks are spiritual and mental, so is the defense. THE FULL ARMOR OF GOD MENTALLY AFFIRMS AND DEFENDS EACH TRUTH OF OUR IDENTITY IN CHRIST.
Belt of Truth
Could there be a reason Paul listed the Belt of Truth first? I think the answer is yes, a very good reason.
Going as far back as Eve, we see that God's revealed truth is often both target and the route of attack (“Yea, did God say…?”). The grievous trials Satan was permitted to lay upon Job were a test of the man's faith in the truth that God was invariably good and just no matter our worldly circumstances. But while Job knew his afflictions came by the permission of God, he had no idea why any of it was happening. That lack of knowing seems to have been the real agony for Job – the mental anguish of being completely in the dark and tempted to doubt God, rather than the physical horrors he endured.
It is no different for believers today: whatever comes to the us is permitted by God but in forgetting the example of Job, very often our mental pain far outweighs any physical or circumstantial pain that accompanies it. Discouragement, doubt and resentment against God and His Word can result. That is the point of the attacks, just as it was with Job.
As for the Belt of Truth, all commentators note that the belt worn by Roman soldiers held all the primary pieces of armor together. This could explain Paul’s listing it first: every other piece of spiritual armor listed after the Belt also represents a facet of Truth targeted by Satan. So just as the Roman’s belt held the bulk of his armor together, the wearing of these spiritual components is dependent upon faith in the fact that what they say about the believer IS TRUE.
Also note that the Belt (as well as the following two components of armor) seems to already be on the believer without his having chosen to put it on. The Greek here can be rendered, "having put on..." This, too, would make sense: as saved individuals, we HAVE ALREADY believed the Truth of the Gospel; we HAVE ALREADY received the righteousness of Christ Himself before the Father, and we HAVE ALREADY received all this by faith in Christ, by which we also HAVE ALREADY been put in a position of peace with God.
If you are a believer in Christ, you ARE - right now - wearing these three pieces of armor whether you realize it or not. And not only that: you can't take them off. God won't take them back. And Satan cannot get them off of you. For this reason, an accurate knowledge of what these first three components represent is critical to our standing in warfare.
Believers are to not only know but to keep constantly in mind that God's Truth is Satan's usual target of attack, and that all his attacks come by way of some aspect of God's Truth. Thus, knowing and clinging to God's Word is of utmost importance and cannot be neglected if a believer expects to stand on the spiritual battlefield.
Breastplate of Righteousness
It is true that the Roman breastplate protected the heart and vitals and perhaps that has some spiritual relevance here. But as discussed above, the believer has been given the righteousness of Christ Himself and, being counted by God as now dead to His condemning Law, that righteousness is as permanent as it is perfect for it is His, not ours.
The world, the flesh and the devil can gossip, slander and lie whatever they like about us, but if we're in Christ we are perfectly and forever righteous before God in the only judgment that really counts. We HAVE the righteousness of God, no matter what Satan may say.
Shoes of the Gospel of Peace
For the longest time I never understood Paul's point in equating the Gospel to shoes. That the feet of those who share and spread the Gospel of the grace of God are blessed I do not dispute, but I couldn't see how that equated to battle armor.
Then I read how the soles of a Roman soldier's shoes were heavily studded for traction. A few interpreters take from this that the "readiness" here represents not so much an eagerness for evangelizing but the actual solid foundation of the Truth of the Gospel on which we stand as believers. After all, the Gospel of grace is the specific message by which we were saved and by which have peace with God.
The sure foundation upon which we stand in Christ is Paul's Gospel, and no other foundation has been or can be laid by any man. Any other gospel, or admixture of gospels, is a false foundation that is in fact no foundation at all. If you have believed the Gospel of the grace of God, you HAVE peace with God no matter what Satan or your attacked mind and emotions may say!
Shield of Faith
At this point I defer to the usual interpretations. If our faith in the Truth we've already received (as represented by the other components) momentarily fails, we are left wide open to attack. This is indicated by the command to "take up the Shield of Faith. “If we give in to the flesh and sin, and Satan uses that failure to attack our righteousness, how are we to respond? We are to respond in faith by reminding ourselves that we HAVE the righteousness of Christ and are forgiven for His name's sake. If we suspect a false teacher is seeking to seduce us with an especially subtle false doctrine, what can we do? We are to respond in faith that we HAVE the Truth, and we then use the Word rightly divided to prove their error. If a cultist presumes to tell us we're unsaved, how do we reply? By reminding ourselves of our solid foundation in the Gospel of Peace, by which we have been saved and by which they may be saved, too.
Helmet of Salvation
Since the prior components establish that we stand firm on the Gospel we've believed, have peace with God, and have the righteousness of Christ, here again I would agree with nearly all commentators that the Helmet represents the fact of the yet-future aspect of our salvation. We are not left alone in this world. Christ is sure will return for us. In the meantime, we're to stand strong for Him by standing strong in Him.
Sword of the Spirit, the Word of God
As is often commented, this is the only offensive weapon among the armor's components. Christ Himself used it against Satan three times and Satan fled.
Even though we are expected to stand firm and are not told to go on any kind of spiritual ground-gaining counterattack, the believer who has indeed "put on the whole armor of God" including the Sword will be unassailable under attack, equipped for taking captive every though and for the tearing down of strongholds. In fact, just reminding ourselves of verses pertaining to each component – for example, Romans 3:22 for the imputed righteousness of Christ - is to wield the Sword of the Spirit!
A final note
While the armor is supplemented with necessary prayer - an absolute must - it is interesting to note that the components themselves end where they began: with TRUTH: first as the general Belt of Truth that we possess by virtue of having been saved, finally with the actual Word of Truth which we're to wield in the face of attack. This aligns with the common understanding that our spiritual battle takes place primarily in our minds and hearts, where Truth is either accepted and acted upon, or neglected or rejected, with defeat the sure result.
Satan's attacks against the believer WILL target one or more of the above pieces of armor because each piece represents a vital truth about who we are in Christ. If we fail to defend an area, we remain safe in Christ but our Christian walk is needlessly impaired. So when attack comes, what are we to do?
When Satan assaults you with accusations of guilt and condemnation after you fall into sin, he's attacking your righteousness in Christ. Remind yourself IT IS WRITTEN that you are dead to the condemning Law (Gal 2:19) and now wear the righteousness of Christ Himself, therefore God not only doesn't want to condemn you, by His own decree He cannot legally do so (Rom 8:1). Nor can Satan!
When Satan seeks to beguile you with what you suspect is false doctrine, he's attacking the truth. Remind yourself IT IS WRITTEN that it's not God authoring this confusion (1 Cor 14:33) but, rather, that you possess the Truth in the very Spirit and mind of Christ (1 Cor 2:16). Satan is the author!
When Satan causes you to begin to doubt your salvation, he's attacking your peace with God. Remind yourself IT IS WRITTEN that you've believed the Gospel of the grace of God and are made forever at Peace with Him thereby, for God cannot lie (Titus 1:2). Satan cannot remove you from God's loving hand...nor can you!
When Satan worries you that God is not watching over you, doesn't care, or has abandoned you to the world, he's attacking the security of your salvation. Remind yourself IT IS WRITTEN that He has He has numbered - not counted, NUMBERED! - the hairs on your head (Luke 12:7), knows and will meet all your needs (Phil 4:19) and promises you the fulfillment of your Salvation at the soon return of Christ (Titus 2:13-14) which Satan cannot prevent or delay!
All this, do in Faith (your Shield) and you cannot fall, shall not crawl, will not stumble, cannot fail but will STAND on the battlefield as commanded!