17 Two more items remain. The "helmet" covered the head. It was made of bronze with leather attachments. In Isa 59:17 the Lord wears "the helmet of salvation" along with the "breastplate of righteousness." Christians share that divine equipment. The verb "take" reflects that the helmet and sword were usually handed to a soldier by his armorbearer. This verb is appropriate to the "givenness" of salvation. In 1Th 5:8 the helmet is identified with the hope of full salvation; this may well be the inference here (Eph 1:18).

The final weapon is the "sword," the short two-edged cut-and-thrust sword wielded by the heavily armed legionary. The "sword of the Spirit" is the Christian's only weapon of offense—meaning either the sword that is supplied by the Spirit or that is used by the Spirit. "The word of God" is the divine utterance or speech. In Isa 11:4 the Messiah is portrayed as one who strikes the ruthless with the rod of his mouth (i.e., by the authoritative impact of what he says).

But what specifically is this utterance of God? Some suggestions are the recorded words of Scripture in the OT, the remembered sayings of Jesus, or apostolic sayings that were incorporated into the NT. Others regard it as words given by the Spirit to meet the critical need of the moment (cf. Mk 13:11), or as prayer in which the Spirit speaks through the Christian (v.18). The best interpretation is probably the most obvious; it refers to those words that the Spirit has inspired so that Christians may use them to drive away Satan. It is significant that in Matthew's temptation narrative Jesus himself (quoting Dt 8:3) refers to "every word that comes from the mouth of God" (Mt 4:4) and employs relevant Scriptures to defeat the devil's stratagems.

11 The call to "put on" God's armor recalls a similar appeal in 1Th 5:8. This accoutrement is provided by God and modeled on what he wears himself (Isa 11:5; 59:17). It is a complete outfit ("full armor," also v.13). The soldier must be protected from head to foot, and his armor is made up of all the various pieces, both defensive and offensive.

"Stand" is a key word in this passage (cf. vv.13-14). It is a military term for holding on to one's position. The equipment enables the soldier to ward off the attacks of the enemy and to make a stand against him. Before any offensive can be launched, one must first of all maintain his own ground. The fourfold use of "against" stresses the determined hostility confronting the Christian soldier. The commander-in-chief of the opposing forces is the devil himself, the sworn enemy of the church. He is a master of ingenious stratagems and his tactics must not be allowed to catch us unawares. These stratagems probably reflect his deliberate attempts to destroy the unity of Christ's body (3:14-22; 4:1-16, 21) through the invasion of false doctrine and the fomenting of dissension (4:2, 21, 31-32; 5:6).

5:8 Your enemy the devil prowls around like a roaring lion. Satan prowled as he traveled around the earth seeking harm in Job 2:2. In Job’s Hebrew text, “Satan” appears to have been a title, meaning “enemy” or “accuser”; he may have functioned in Job as a sort of prosecutor. Satan’s malevolent character, however, quickly grew clear (cf. Zec 3:1 – 2), as it was in both Jewish tradition and the NT. devil. Originally meant “slanderer.” Jewish tradition emphasized Satan’s role as accuser, deceiver and tempter, seeking to lead people astray from God; many Jewish people believed that the present age was under the devil’s dominion. like a roaring lion. An adversary (Ps 22:13) or even exploitive rulers (Pr 28:15; Eze 22:25; Zep 3:3) could be like “roaring lions.” Lions were considered the most powerful predators; eventually some Christians were fed to literal ones.