The last two items of armor are the ones a literal Roman soldier would take up last. The helmet of salvation is an allusion to Isaiah 59:17 where the Greek OT uses some of the same terms Paul uses in the armor of God analogy. There, Yahweh is revealed as the divine warrior who goes to battle for the sake of His people.

We point out that Paul does not cite the vengeance part of the OT verse. This is like Jesus citing Isaiah 61:1, 2 about Messianic salvation (cited in Luke 4:18, 19) but leaving out the vengeance part. The reason for these omissions is not that vengeance will not happen, but that they do not happen during the first advent or the church age. They will happen in the events of the second advent.

Much mischief has been done in church history by failing to understand this and starting religious wars in the name of the church. The church age is about standing firmly in the gospel truths of God’s armor and proclaiming the gospel so that people are rescued from the domain of Satan and brought into God’s kingdom. We explain that this transfer from one kingdom to another is not geographical but spiritual. We do not wrestle against flesh and blood. The Holy Spirit inspired the Scriptures and the use of the “sword” is the preaching of the Word of God. Believers were rescued from bondage to sin and Satan and are now the redeemed children of God by faith in His word which we proclaim with boldness.