The mind is a most interesting battlefield. It is the ground upon which good and evil battle. The mind has been said to be a prison of thoughts, I will expand on that thought. These thoughts constantly bang on the walls of the prison seeking to be let out. They will be let out, in our very words and actions our thoughts are expressed, they reveal themselves in the path one takes. Now the thing is the most noticeable thoughts are either corrupt in nature, or the very expression of righteousness. This is why it is important to keep to the Christian discipline of prayer, devotion, and forming strong brotherly/sisterly council, that the thoughts of righteousness may be appeased at the crucifixion of those that are corrupt.
The mind is a weapon, the righteous can overcome those thoughts of corruption and shatter them. He must take every thought captive, but the corrupt man can not destroy the thoughts that are righteous. No, what the wicked does is a much scarrier thing, he can taint those thoughts that are good and make them corrupt just to appease the demon (destructive being) of self. With the mind you can cause destruction, or you can bring growth. The mind is a most intriguing thing.