6:14 truth. The “whole armour of God” (Ephesians 6:11,13) involves seven units, all of which are vital if we are to prevail lastingly in the spiritual conflict with the great enemy of our souls. We must, first of all, be strongly girded about with truth—that is, the Word of God, and all its counsel (John 17:17; Acts 20:27)—if we hope to stand against the father of lies (John 8:44).
6:14 righteousness. The “breastplate of righteousness,” protecting the heart and lungs which provide life and breath to carry on the fight does not refer to personal righteous behavior (always imperfect at best) but His righteousness, imputed to us and in us (I Corinthians 1:30; II Corinthians 5:21) through faith by grace and thus eternally impregnable.
6:15 peace. The feet also must be prepared, shod with footgear able to move quickly and as far as the gospel requires. “How beautiful are the feet of them that preach the gospel of peace” (Romans 10:15). Satan would bring doubt and rebellion and death, but the whole gospel, from creation to redemption to consummation, brings assurance and peace and life.
6:16 shield of faith. The Roman shield was metallic and thus invulnerable to the ignited missiles often fired by opponents, especially when the entire phalanx mounted shield adjacent to shield, giving a solid wall of advancing metal. The shield is faith, and faith in God’s promises is “the victory that overcometh the world,” especially that promise that the Creator, the Son of God, has also become, in Jesus Christ, our eternal Savior and Lord (I John 5:4-5).
6:17 word of God. The “sword of the Spirit” (note Hebrews 4:12) is not the logos (that is, the Word as a whole) but the rhema (that is, the individual text, or “saying,” of the Word) that is applicable in each particular situation and Satanic attack. Thus Jesus defeated Satan at each temptation merely by citing the appropriate Scripture (Matthew 4:4,7,10).