Some of your thoughts are not your own. Some of them did not originate with you. The enemy tries to plant thoughts in our minds that are lies, deception, and/or condemnation. These demonic thoughts projected into our minds are the “flaming arrows of the evil one” mentioned in Ephesians 6:16.
So, we know the kingdom of darkness can whisper lies to us, but can demons read our thoughts?
I had an encounter once where I was praying for a woman in my church who was physically sick, and I was just praying for healing. As I prayed for healing she had no outward, physical signs of the demonic. Yet, as I prayed, I sensed the Lord highlight the possibility that she had demons in her causing some of the problems. So without saying a word, I shifted in my thoughts from “healing prayer” to “deliverance prayer.”
As soon as I shifted my thoughts and directed them against the demons, even thought I never prayed out loud, she started to have physical manifestations of the demonic. She started to dry-heave and gag (common signs of demons trying to leave the body) just as I turned my thoughts from healing prayer to deliverance mode. Obviously the demons somehow picked up on the change in my thoughts.
Did they read my thoughts? I’m not sure. I believe that as soon as my thoughts changed from healing prayer to “commanding demons to leave,” something was released out of me in the spirit realm…maybe light or power or something to which the demons reacted. It’s possible that demons can pick up when our thoughts agree with God and when they agree with a lie from the enemy. Maybe there is something released in the spirit realm that they can pick up on from our thoughts and emotions.
This could explain why Jesus was very concerned with our thought life and the condition of our hearts. What if every thought you have and every emotion either repels the kingdom of darkness or invites it. What if every thought you have and every emotion either strengthens the angels around you and the Kingdom of God or diminishes it. This is why we must “take captive every thought to make it obedient to Christ” (2 Corinthians 10:5) and stop thinking that our thought life is in any way “private.”