All three have influences in our thoughts. Our thoughts are our own, however, good or evil (James 3:13-15). We are responsibile for our every thought as well as our every word and every deed. Demons don't control our thought life. We yield ourselves to their deception by neglecting the Word and prayer. We are tempted because of our own lusts - which are fed and nurtured by the world, the flesh, and the devil.

This is why we are told to think on things which are pure (Philippians 4:8) and to be spiritually minded (Romans 8:5-7). It is the washing and renewing of the mind that transforms believers into the image of Christ (Romans 12:2).

-R