Back when Mrs. Kay Gabbard warned me about always putting on the armor of God, I did a little study on the actual pieces of the armor. This is what I found:
1. Belt of Truth - Satan fights with lies, and sometimes his lies sound like truth; but believers have God's truth, which can defeat Satan's lies. Living a life of honesty and integrity enables the Christian to be one in purpose with Jesus Christ, who is the Truth, and to be unhindered in the battle against Satan. You must be able to differentiate between Satan's lies and God's Truth to truly be able to win and live victoriously (and you can live victoriously no matter your circumstances).
2. Breastplate of Righteousness - Satan often attacks our heart--the seat of our emotions, self-worth, and trust. God's approval is the breastplate that protects our heart. He approves of us because we have trusted Christ to save us and cleanse our hearts from sin. The breastplate covered the body from neck to thigh. The heart must be kept pure and righteous because sin gives a foothold to the enemy. Confession and forgiveness cleanse the heart.
3. Shoes of the Preparation of the Gospel of Peace - or, readiness to spread the Good News. Satan wants us to think that telling other the Good News is a worthless and hopeless task--the size of the task is too big, and the negative responses are too much to handle. But the "shoes" God gives us are the motivation to continually proclaim the true peace that is available in God--news everyone needs to hear. Be about your Father's business. The Roman soldier wore sandals with cleats made of sharp nails designed to give firm footing on even the most rugged terrain.
4. Shield of Faith - with which you can extinguish all the flaming arrows of the evil one. The shield of faith protects us from Satan's flaming arrows in the form of insults, setbacks, and temptations. With God's perspective, we can see beyond our circumstances and know that ultimate victory is ours. The fiery darts try to instill doubt, fear, and guilt. Faith acts as an invisible shield that deflects such false accusations. The Roman shield was a long, oblong, or oval shield which was crafted from two layers of wood covered with linen or animal hides, bound together with iron. When fighting side by side, soldiers could hold these shields together to form a long wall (speaks of the power of a group of like-minded believers). Soaked in water, they served as adequate defense against the enemy's "fiery darts"--arrows that had been dipped in pitch and ignited. The shield of faith offers God's unlimited resources of power and wisdom to resist the fiery darts of distressing circumstances and temptations to evil.
5. Helmet of Salvation - Satan wants to make us doubt God, Jesus, and our salvation. The helmet protects our mind from doubting God's saving work for us. A helmet protects the head, that is, the brain and thoughts. Assurance of salvation is a mighty defense against doubt and insecurity and the kinds of works bred by them. The Roman soldier's bronze helmet had leather attachments to hold it in place. Christians can experience protection from Satan's attacks as they rest confidently in their position as members of God's family, set apart for His purposes. Further, they can know God's present work of sanctification in their lives, experiencing deliverance from sin and having the guarantee of future, eternal deliverance from every kind of evil.
6. Sword of the Spirit - which is the Word of God. The sword is the only weapon of offense in this list of armor. There are times when we need to take the offensive against Satan. When we are tempted, we need to trust in the truth of God's Word. The Word of God was used by the Lord Jesus against Satan. The living Word is powerful, effective, and instructive. The Roman soldier's short, two-edged sword enabled the heavily-armed soldier to attack deftly and defeat his enemy at close range. The believer's sword may be understood to be either "supplied by the Spirit" or "used by the Spirit." Paul further identified this sword as "the Word of God." "Word" most probably refers to specific sections of Scripture the Holy Spirit brings to mind to meet a particular need (therefore, you must know the Word). All of the armor is obviously important, but basically if you don't know the Word and if you can't hear personally from God, then you don't know true Truth (even though you may think you do), so the Sword of the Spirit, or the Word of God, is very important and ties into all of the other armor.
And, we can't forget what Paul tells us after he lists out the armor...PRAY. Pray in the Spirit on all occasions with all kinds of prayers and requests.
Prayer - In the midst of battle, we as believers must keep in constant communication with our Leader for directions and encouragement. Our prayers for one another are important and effectual. Prayer is to be constant as the Christian prepares for battle, engages in it, and rests from it. All kinds of prayer are to be offered through the power of the Holy Spirit.