6:12 darkness of this world. The curtain of the invisible is slightly opened here to give us a brief glimpse of the tremendous spiritual forces arrayed against the people of God. God created “an innumerable company of angels” (Hebrews 12:22), and apparently at least a third of this host of created spirits have followed Satan in his long war against God and His people (Revelation 12:4,7). These are organized into a great hierarchy of principalities and powers, the rulers of the darkness of this world. We dare not be without God’s whole armor when wrestling against such powers. Nevertheless, “greater is He that is in you, than he that is in the world” and “they that be with us are more than they that be with them” (I John 4:4; II Kings 6:16). If we, using God’s armor, “resist the devil,” then he and all his minions “will flee from” us (James 4:7).

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 helmet of salvation. This helmet is called “the hope of salvation” in I Thessalonians 5:8, and such a hope is, indeed, a hope involving “full assurance…unto the end” (Hebrews 6:11). Salvation involves an eternal future salvation as well as a past acceptance and present assurance thereof. It is that certain hope that protects the believer’s mind as he would, in this spiritual warfare, seek continually to be “casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ” (II Corinthians 10:5).

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).

6:18 Praying always. Persevering prayer, not just for personal deliverance, but also in supplication for others, is the invisible, but powerful, weapon that assures that God Himself, with His angels, is also fighting for us.

6:19 mystery. Once again (see also Ephesians 1:9; 3:3-4,9; 5:32), as he closes the epistle, Paul speaks of that past mystery hidden in God since creation, which he now wants boldly to make fully known.