Be strong in the Lord and in the strength of his might. Put on the whole armor of God.
Strong in Someone Else's Strength
The famous passage opens by relocating the strength: 'be strong IN THE LORD and in the strength of HIS might.' Before a single piece of armor is named, the battle is declared un-winnable by personal grit. The armor is not the believer's resourcefulness; it is God's own equipment, lent. Spiritual warfare in Ephesians begins not with aggression but with dependence.
The Real Enemy
'We do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers... against the spiritual forces of evil in the heavenly places.' Paul names what Colossians 1 already filed under 'created through him and for him' (and 2:15 under 'disarmed'): real, personal powers — but created and defeated ones. The verse does two things at once: it takes evil seriously enough to name it, and it refuses to let the Christian treat other people as the enemy. The fight is never finally against the neighbor.
Stand
The verb that governs the whole passage is not 'attack' but 'stand' — four times. The armor is for holding ground already won, not seizing new territory by spiritual force. And every piece is something Ephesians has already said belongs to the believer in Christ: truth (1:13), righteousness (4:24), the gospel of peace (2:17), faith, salvation (2:8), the word and the Spirit. To 'put on the armor' is to consciously wear what grace has already given — to stand in Christ's benefits when they are tested.
Prayer Is the Air, Not a Seventh Weapon
The list ends not with a weapon but with the atmosphere of the whole: 'praying at all times in the Spirit.' The armed believer is a praying believer — and praying 'for all the saints,' not just for self. Paul, the prisoner, asks finally for boldness to keep speaking the gospel. The point of standing firm is that the mouth keeps proclaiming Christ.
Christ, the Armor Himself
The deepest reading, as old as the Fathers: the armor is Christ. Paul drew it from Isaiah, where it is GOD who wears righteousness as a breastplate and salvation as a helmet (Isa 59:17). To put on the armor of God is, finally, to 'put on the Lord Jesus Christ' (Rom 13:14). The warfare ends where all Theologos spiritual-warfare studies end: not in fear of the dark powers, but in the supremacy of the Lord who has already disarmed them, worn now as truth, righteousness, and peace.
Go deeper: Pneuma — praying in the Spirit (Lexicon) · Pistis — the shield of faith (Lexicon) · Christus Victor — the powers disarmed (Glossary)