And take the helmet of salvation That is, the hope of salvation, as it is expressed in the parallel passage, 1 Thessalonians 5:8. The helmet was for the defence of the head, a part which it concerned them most carefully to defend, because one stroke there might easily have proved fatal. Thus it concerns the Christian to defend his mind, courage, and fortitude against all temptations to dejection and despondency, by a lively hope of eternal life, felicity, and glory, built on the promises of God, which ensure that salvation to those disciples of Christ, whose faith continues to the end to work by love. Armed with this helmet, the hope of the joy set before him, Christ endured the cross and despised the shame. Hence this hope is termed (Heb 6:19) an anchor of the soul, sure and steadfast, entering into that within the veil. Hitherto our armour has been only defensive: but we are to attack Satan, as well as to secure ourselves. The apostle therefore adds, and the sword of the Spirit, which is the word of God Here the apostle calls the word of God the sword of the Spirit, because it was given by inspiration of the Spirit; and because the doctrines, promises, and precepts of it, are the most effectual means of putting our spiritual enemies to flight. Of this efficacy of the word of God, we have an illustrious example in our Lord's temptations in the wilderness, who put the devil to flight by quotations from the Scriptures of the Old Testament. And if we would repel his attacks with success, we must not only take the fore-mentioned shield in one hand, but this sword of the Spirit in the other; for whoever fights with the powers of darkness, will need both. He that is covered with armour from head to foot, and neglects this, will be foiled after all.
We may observe here, with Beza, that all the parts of the complete armour of the ancients are elegantly introduced in the apostle's account of the Christian's complete armour. For there is, first, the military belt, called by the Greeks ζωστηρ, and by the Latins balteus. This covered the two parts of the breast-plate where they joined. The breast-plate was the second article of the complete armour, and consisted of two pieces; the one reaching from the neck to the navel, and the other hanging from thence to the knees. The former was called θωραξ, the latter ζωμα. Accordingly, in the parallel passage, 1 Thessalonians 5:8, the breast-plate is said to consist of two parts, faith and love. Next to the breast-plate were the greaves, which made the third article of the complete armour. They were called by the Greeks κνημιδες, and by the Latins ocreæ, and were made of gold, or silver, or brass, or iron, and were designed to defend the legs and feet against the strokes of stones or arrows. Thus Goliah had greaves of brass upon his legs, 1 Samuel 17:6. The fourth article of the complete armour was the helmet, which likewise was made of metals of different sorts, and was used to defend the head against the strokes of swords, and missile weapons. Add, in the fifth place, the shield, and the whole body is completely covered. But, besides the defensive armour, just now described, offensive weapons were likewise necessary to render the soldier's armour complete; particularly the sword, to which, as we have seen, the apostle alludes, in speaking of the Christian armour. They had darts, likewise, or javelins, referred to Ephesians 6:16. This whole description, given by St. Paul, shows how great a thing it is to be a Christian: the want of any one of the particulars here mentioned makes his character incomplete. Though he have his loins girt with truth, righteousness for a breast-plate, his feet shod with the peace of the gospel, the shield of faith, the helmet of hope, and the sword of the Spirit; yet one thing he wants after all. What is that? It follows in the next verse.