We are not carrying on a physical war, but the battle for us is no less real. We need to understand that we are not fighting for material success, earthly power, or social prestige. We are not even trying to make our enemies look bad. The real issue is the victory or defeat of God's purpose for our lives.
We must realize that we have merciless, implacable, and powerful spiritual enemies, so that such things as human cleverness, ingenuity, organizing ability, eloquent arguments, charm, or forcefulness of personality are simply not the answer. Those things may impress men, but they in no way impress demons. Those things are the weapons of carnality, of flesh.
The good news is that the Captain of our salvation has already defeated their Goliath. Their leader is defeated, beaten, and the Victor lives in us, lending us His strength and insight.
Paul indicates that the enemy invades our minds, our imaginations. He does this through opinions, convictions, and feelings that exalt themselves against the knowledge of God. Paul uses the phrase, "casting down arguments," in verse 5. Some Bibles render arguments as "reasoning," "convictions," or "opinions." Even "feelings" would be appropriate to the thought. Whatever the application, these arguments exalt themselves against the knowledge of God.
These satanic thoughts or attitudes are designed to affect or alter first our minds and then our behaviors. Satan did this to Eve in the Garden of Eden (Genesis 3:1-6). These wrong reasonings are the key to understanding what Satan is trying to accomplish.
God created humans with the ability to reason, but what line of reason should a Christian follow? We can grasp what not to follow by considering Paul's phrase, "against the knowledge of God." In other words, the thoughts that invade our mind, which come from this evil, wicked, subtle, deceitful spiritual leader, will lead us to exalt or prioritize our reasoning above God's knowledge.
This knowledge is not primarily about God, but the knowledge He has revealed. Knowledge about God is certainly included, but what Satan desires is for us to exalt our ideas over godly and true knowledge and understanding.
Why would he want to do this? Because we have a relationship with a Person—a Being with personality, character, and a wonderful, wholesome way of life that produces every good thing. Satan tries to destroy that relationship by getting us to doubt either the Person and His goodness or the rightness and goodness of His promises and way of life.