These are critical parts of our spiritual armor. We are, by obeying these verses, wrapping ourselves in the power and strength of God. The loins in a human are the region of the hips, groin, and lower abdomen. As such, a very delicate part of the human anatomy and one if left unprotected and injured, can lead to serious consequences. Paul says here to gird (fasten with a belt or band) this part with truth. However, what is truth? Jesus, when praying for the disciples, said, "Sanctify them by Your truth. Your word is truth." (John 17:17)
The Bible represents the ultimate truth. If one is not living by the word of God, then his or her life is incomplete and worldly. Living by the truth of God’s word on a daily basis will protect us from great spiritual injury which could lead to spiritual death: "and having shod your feet with the preparation of the gospel of peace;" (verse 15)
As with the loins, if the feet or ankles of a soldier do not have armor and injured, he is at a great disadvantage because he cannot keep up with the rest of the army. The same is true with the way that a Christian walks. Is one constantly stepping on other’s toes, thus creating strife? On the other hand, does that person create peace by what they say and how they walk?
"Above all, taking the shield of faith with which you will be able to quench all the fiery darts of the wicked one." (verse 16)
As with a breastplate, the shield of a soldier is part of his armor used to ward off swords, spears, and arrows. Without the faith of Jesus Christ, a Christian will not have a shield to ward off the attacks of Satan and his demons. When we shield ourselves with righteousness, there is no evil spirit – even Satan himself - that can touch us. There is no greater protection: "And take the helmet of salvation, and the sword of the Spirit, which is the word of God;" (verse 17)
As with the loins, the head is also an area that can suffer from a serious injury. Being that the skull protects the brain, it is quite vulnerable to injury in certain situations. A helmet will protect the skull and brain from injury. In like manner, once the Father calls someone to salvation, that person must put on this spiritual helmet of faith in order to maintain his or her calling. The sword of the Spirit, the only offensive part of our armor, is the word of God or the Holy Bible. It is man’s instruction book designed to teach him how to live his life on earth. Without the Bible in our daily life we have no weapons which to fight lies, deceptions and the devil.