Put on the whole armour of God, that ye may be able to stand against the wiles of the devil.
Note 2 at Eph 6:11: Paul said to put on the whole armor of God. Just using part of God's armor will not fully protect us. Many of us Christians have been running around with our helmets of salvation on and nothing else. There is more to overcoming the devil than just being saved. We have to understand our righteous position (see note 12 at Eph 6:14) in the Lord, faith (see note 14 at Eph 6:16), the Word (see note 18 at Eph 6:17), and the Gospel of peace (see note 13 at Eph 6:15).
Note 3 at Eph 6:11: Notice that this is the armor of God that we are told to put on. God didn't just provide us with armor; He gave us His armor. Isa 59:17 specifically mentions the Messiah wearing the helmet of salvation and the breastplate of righteousness. Certainly, God's armor is more than sufficient if we will just wear it and let it work.
In Eph 6:10, Paul said we were to use God's power and might. Here, he told us to use God's armor. If we are dressed like God and fight like Him, we'll look like God to the devil. The devil won't realize we are not God unless we tell him through some statement or act of unbelief.
Note 4 at Eph 6:11: The American Heritage Dictionary defines "wile" as "1. A stratagem or trick intended to deceive or ensnare. 2. A disarming or seductive manner, device, or procedure." This word is denoting trickery and deceit. The word "wiles" is an old English word that is similar to such words as "methods," "strategies," "schemes," "tactics," and "devices." Just as the success of football players, boxers, or soldiers depends partly on how well they know their opponents, so believers must not be ignorant of Satan's devices.
Jesus stripped Satan of all his authority (Mt 28:18). The power that Satan uses against man now is deception. Those who ascribe other powers to him have already fallen prey to one of his lies. The devil deceives people and uses their own power and authority against them. The thing that makes deception so deadly is that those who are deceived don't know it. Once they realize they are deceived, they aren't deceived anymore. The truth of God's Word will remove the deception of the devil and thereby break his power in people's lives.