The Scriptures teach that Satan and his kingdom have little power over Christians. Therefore the only way he has to attack believers is by spreading false doctrine in order to divide and confuse us.
In order to accomplish this Satan has confused some into thinking we fight him by means other than teaching correct doctrine. The moment we realize we are fighting incorrectly and change our strategy then Satan has something to worry about. Until then no matter how hard we fight it ether does him no harm or actually adds to the confusion, so he is pleased. 
The following scriptures are usually taken out of context in order to allow some to think they are fighting against Satan while all the while doing just the opposite.

2 Corinthians 10:4 the weapons we fight with are not are not weapons of the world. On the contrary, they have divine power to demolish strongholds. We demolish arguments and every pretension that sets itself up against the knowledge of God. And we take captive every thought...

Here Paul is stating that his teaching tears down every false thought or doctrine, the stronghold Satan would use to keep every Christian from maturing. Satan would rather have us think this means we should control our thoughts in order to stop sinning.

Ephesians 6:11-12 Faith is our shield and the word of God is our sword

If our faith is in a misinterpreted passage of scripture we will fail.

Isaiah 45:11 do you question me about my children, or give me orders about the work of my hands?

Here God is saying he make the decisions not us, we should not dare to try to command him to do something, and yet in some of the spiritual warfare classes you would take today they quote this in the King James version in such a way as to say we are to command God.

Matthew 16:19 I will give you the keys to the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.

After talking to the disciples about the evil doctrine of the Pharisees, Jesus was telling the disciples that they, not the Sanhedrin, would make the decisions for the saints. Binding and loosing had always applied to who had the authority to properly interpret the laws of God. In order to stay away from legalism or liberalism. Yet today some teach this refers to us biding and loosing demons.

Luke 10:19,9 the disciples were to cast out demons and to heal the sick.

When the disciples were granted the power to heal the sick and cast out demons, they did this consistently from town to town. If you as a Christian can't heal the sick every time you try, why would you think you can cast out demons every time you try?

2 Corinthians 1:18,20 our message to you is not "yes" and "no." For no matter how many promises God has made, they are "yes" in Christ.

Paul is saying he did not change his mind about coming to them. God used the situation to detain Paul so that others would here the gospel. God is always faithful and his plans always work out, although sometimes no in the way we would think.   Yet today some are teaching this means all the power God gave the disciples (casting out demons and healing the sick) are ours if we only claim it. Such a teaching is the sin of presumption.

These and other passages are often used by people who put on these spiritual warfare classes. Instead of equipping people to combat Satan's attempts at spreading false doctrine, they are trapped in a mindset that prevents them from doing just that.

All quotations taken from the NIV unless other wise noted.