The section in Ephesians 6 where Paul speaks about the spiritual armor is well known. Perhaps less well known is that Paul derives the imagery in these verses directly from the Old Testament, namely from the prophet Isaiah. And to think that there are quite a few believers who believe that Paul, in the Epistle to the Ephesians, where he sets out the truths regarding the ecclesia, the body of Christ, would not appeal to the Old Testament.
When we look up the verses in Isaiah, we see that it is God Himself who puts on this armor.
Isaiah 11 NIV
5 For righteousness shall be the belt around His hips, and truth the belt around His waist.
Isaiah 59 NIV
17 For He put on righteousness as a breastplate and placed the helmet of salvation upon His head. He put on the garment of vengeance as clothing and clothed Himself in jealousy as a cloak.
He wages the battle
In these verses, it is the Lord who wages the battle, just as God already said to Moses: YAHWEH will fight for you, and you, you shall be silent (Ex. 14:14). It speaks of Him who will come to set things right and to defeat His enemies (Isa. 11:4). Of God who will come to repay (Isa. 59:18) and of Him who achieves victory in the battle over His enemies and delivers His people (Isa. 59:20).
stand on His victory
When Paul cites this imagery from Isaiah in Ephesians 6 and speaks of “the armor of God,” he does not refer (merely) to the fact that we receive this armor of God, but that it is God Himself who clothes Himself in this armor and that He is the one who fights and conquers. For us, therefore, the armor consists only of weapons of defense, to ward off what comes at us and to stand firm, in His victory!
Ephesians 6
13 Therefore take up the whole armor of God, so that you may be able to withstand in the evil day, and having done everything, to stand firm.