The Greek indicates that you put it on once and for all. Yes, in a sense we put it on every day, but we say, ‘O Lord, I see my perpetual need of the means that thou hast provided for me to resist evil and walk in a holy life’, and we re-apply it every day.
Can we simplify these pieces of armour to just one piece? There is one evangelical preacher in the United States who with good intentions has greatly popularised a simple approach, if we can call it that, to sanctification. If you can only find a way to be rejoicing in God constantly, then that will look after everything. Some call it Christian hedonism – enjoying God – and if you live to enjoy him everything else will follow. You will be able to resist sin, you will be able to stay close to the Lord. But when we look in the Scripture, we find it is much more serious than that. These theories of sanctification that simplify things down to one matter, might be well intended but they are not Scriptural. The apostle Paul gives us six items of armour, six methods to keep in mind, in order to resist the devil and maintain holiness. It cannot be all included in one. Others tell us, all you have got to do is to see Jesus. If you can only keep him in view, you will never sin. Still others say, all you have got to do is abide in Christ; it is sanctification by faith. If you strive and try to resist sin, they say, you will fail. You have got to discover sanctification by faith in the same way you discovered justification by faith. It is passive, you do nothing. Disaster! The apostle says, ‘No, you have got six parts of the armour to put on’ and we need to focus on all of them. If you go out into the field of battle with the helmet but no breastplate, you will be easy prey. We need the whole armour of God, and we need to check out what we are employing, not just some parts.