You will find that scripture in 1st Corinthians 2:16. It applies to the person that has made Jesus Christ the Lord of their life. Old things have passed away and all things have become new...one of those things is a new mind...the mind of Christ.
I am a bit uneasy by that first as there are many moments where I do not feel that my mind is thinking like Christ at all. Have you ever been there? Certainly the Lord would not have had that thought!
To operate with the mind of Christ requires you and I to be DILIGENT and dedicated to read the Word so that our mind can continue being renewed. I realize that my mind needs fresh manna every day in order to stay crisp and sharp.
Today, stop beating yourself up over thoughts that you seem to have that seem off the beaten path. Ask God to make His word fresh and alive to you and to keep reprogramming your mind to be more in tune with Him. Just because you have the mind of Christ does not mean that you can't allow the mind of the world to influence you. What it does mean is that God can and will renew and reboot your mind whenever you ask Him to. God did not give you and I a spirit of fear or timidity but of power, love and a SOUND MIND. A mind of Christ is a terrible thing to waste!