2 Corinthians 10:3-5; "For though we walk in the flesh, we do not war after the flesh: For the weapons of our warfare are not carnal, but mighty through God to the pulling down of strong holds; Casting down imaginations, and every high thing that exalteth itself against the knowledge of God, and bringing into captivity every thought to the obedience of Christ."(KJV)
The scripture above throws light on the activity of the mind. The bible says that as a man thinketh in his heart so is he (Proverbs 23:7a), the heart here means our mind because the physical heart only pumps blood to different organs of our body.
It's a fact that, what the brain is to the nervous system, the mind is to the soul and what the nervous system is to the body, the soul is to the spirit. Therefore our mind is responsible for the outcome of our lives since the spiritual controls the physical.
Now there are thoughts called "strongholds", these thoughts fight against the things of God in our mind through unbelief. These strongholds develop with time when we give our mind to things that are against or contrary to the word of God.
Do not let wrong thoughts rule your mind, thoughts that are contrary to the word of God, it will only ruin your life. Cast them down! The devil will only succeed in winning you over if your mind is captured in rebellious thoughts. Think righteously and God will shower his glory upon you.
Philippians 4:8 says; "Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things."(KJV)
Heavenly Father I thank you for your word, I cast down every stronghold operating in my mind against the knowledge of Christ, I refuse to let the devil take hold of my reasoning, I have the mind of Christ. I have victory over every attack in my mind, in Jesus name! Amen!