Romans 6 - Our flesh is the instrument that Satan works through. When we say no to the flesh, we say no to the devil.
If Satan can defeat you in your thoughts then he can defeat you anywhere else as well.
Satan is the master distracter. He is always working to keep us off track in our walk with God.
Satan can control you if you let outward things determine your security.
We open the door for God to work by placing faith in His Word, and we open the door for Satan to work by placing faith in his word. He places thought in our minds that are not true, but can become true for us if they are believed.
1 Peter 5 - Be well balanced because Satan 'roams about like a hungry lion seeking who he can devour.