Ephesians 6:17, “and take the helmet of salvation, and the sword of the Spirit, which is the word of God,”
Paul’s description of the various elements of the armor of God concludes in Ephesians 6:17 with his references to “the helmet of salvation, and the sword of the Spirit, which is the word of God” (Eph. 6:17). As the piece that protects the soldier’s head, the helmet is essential to keeping a soldier alive and conscious, thereby enabling him to continue in his mission. The sword is likewise vital, for it is the weapon with which every fighter can defend himself against blows and fight back against his enemies.
The Lord’s armor in Isaiah 59:17–19 lies in the background of this passage, for God Himself dons a helmet of salvation in that passage to fight against His enemies. This is an interesting image because the Lord certainly does not need to be saved from sin and death as we do. J. Alec Motyer’s superb commentary on Isaiah indicates that in this passage, God’s donning of various armor pieces indicates who He is and what He intends to do. The Lord put on His helmet of salvation in Isaiah’s day to show both the nation of Israel and the entire world that He is salvation itself and that redemption would be accomplished in line with His purposes. For us to put on the helmet of salvation indicates more than our rescue from sin and death. It also means that we arm ourselves with the ability and desire to proclaim to the ends of the earth that salvation is from the Lord. Furthermore, it demonstrates that we will work to accomplish His purposes for the church, the firstfruits of God’s redemption, in line with the instructions of the Lord. All of these points, of course, are outlined in Ephesians (Eph. 2; 4:17–32; 5:1–6:9).
Ancient Roman soldiers carried different weapons, and the sword Paul likely has in view is the short-handled sword used in offensive combat against the enemies of Caesar’s legions. In the Christian life, this sword is the Word of God (Eph. 6:17). Commentators believe Isaiah 11:4 is an important background text here. The Messiah strikes “the earth with the rod of his mouth” in that prophecy so that Paul may be emphasizing the preached Word of God as our offensive weapon against Satan. This makes good sense, for as the Word is preached, sinners are rescued from the Devil’s grip and believers see the sins for which they need to repent.
John Calvin states that “by faith, we repel all the attacks of the devil, and by the word of God the enemy himself is slain. If the word of God shall have its efficacy upon us through faith, we shall be more than sufficiently armed both for opposing the enemy and for putting him to flight.” As we study and proclaim the Word of God to our friends and neighbors, the kingdom of Satan falls.