I have always been led to believe that the armour of God was something we put on as we blasted out into warfare waving our swords ready to put the enemy to flight. It was good discipline to consciously put the armour on every morning, memorise the passage and be ready to fight the enemy! My zeal was, of course, well meant, but lacked a little depth and context.
So what is it really?
Belt, body armour, shoes, shield, helmet - all passive stuff, part of resisting as Paul says in the previous verses. And those shoes - the Gospel of peace, not what I'd call fighting boots! All the pieces form something that protects us, allowing us to stand, not run around fighting.
So what about "taking the sword of the Spirit which is the Word of God"? Jesus is the Word of God! The sword is Jesus. We don't wield Jesus, flinging Him around like a weapon. The Greek word for "take" actually means "receive, accept, welcome". What a difference! The actual fight is His job, we just accept His victory and stand firm, rest in that place with our feet firmly planted in the gospel of peace. Nothing can touch us with that armour on! Sure you can go into lots of detail about each piece of armour if you want, but its all very simple - truth, righteousness, peace, faith, the assurance of salvation, and Jesus doing all the fighting.
Our instruction is simply to take it, that's all! Pick it up and put it on. Not hard, and its right there ready for us, we don't have to run around looking for it because our relationship with Father allows us free access to it - He's holding it out for us ready to slip it on. And once we've put it on we can rest knowing that the enemy can't touch us and Jesus is doing all the hard work! Now we can get on with the important stuff without having to worry about that pesky devil!