"The mind is the battlefield where man first meets with sin. It is the frontier wherein mankind encounters its grim archenemy, the devil.
It is not strange that the enemy should choose man's mind as the battlefield for waging his ferocious struggles. Psychologists say that the mind is the crown atop the human body which directs our actions and behavior whether we are awake or asleep; it controls feelings, awareness, emotions, the will, and thoughts as well. Thus is man's mind the center that controls human behavior.
Therefore if man is defeated in this battlefield, it is the devil that is then in possessions of all man's talents and capabilities. Along with this the devil, as we know him, is a mental force with powers that are extraordinary and varied. However, in spite of all this, he still does not have access to us except through our minds. This is an important fact that many of us need to be aware of - especially those struggling in the realm of virtue, righteousness, and chastity. For although the devil is a formidable spiritual power, the sphere of his activity against man is quite limited. He cannot approach anyone except through the mind, the only part of our nature that is susceptible to doing battle with him - the mind is the target of his attacks."
-Orthodox monk, Father Matta El-Maskeen
Guard your thoughts and be freed from the devil. That is why God commanded us:
"Finally, brothers and sisters, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable—if anything is excellent or praiseworthy—think about such things." Phillipians 4:8
