Put on the whole armour of God, that ye may be able to stand against the wiles of the devil.
The whole armour - "the armour of light" (Romans 13:12) on the right hand and left (2 Corinthians 6:7). The panoply, offensive and defensive. An image suggested by the Roman armoury, Paul being in Rome. Repeated emphatically Ephesians 6:13. In Romans 13:14 it is, "Put ye on the Lord Jesus Christ." On putting on Him, and the new man in Him, we put on "the armour of light," "the whole armour of God." No opening at the head, the feet, the belly, the eye, the ear, or the tongue, is to be given to Satan. Believers have once for all overcome him. On the ground of this fundamental victory already gained, they are ever again to fight against and overcome him, even as they who once die with Christ have continually to mortify their members upon earth (Romans 6:2-14; Colossians 3:3; Colossians 3:5).
Of God - furnished by God: not our own, else it would not stand (Psalms 35:1-3). Spiritual and mighty through God: not carnal (2 Corinthians 10:4).
Wiles - literally, 'schemes sought out; the methodical stratagems' (cf. 2 Corinthians 11:14).
The devil - the ruling chief of the foes (Ephesians 6:12) organized into a kingdom of darkness (Matthew 12:26), opposed to the kingdom of light.