The following is adapted from a Grace Church Q&A session.
Can Satan hear what we say and know our thoughts? Should we avoid praying out loud because Satan might hear us?
There is nothing in the Bible to indicate that Satan is omniscient. There are no verses that say he knows everything or that he can read our thoughts. But he is very adept at predicting human behavior because he’s seen it operate for so long. He can anticipate what you might do in a given situation without knowing your thoughts because of his knowledge of humankind and because he has a supernatural mind.
But in terms of being omniscient and being able to read your thoughts (as God can), the Bible does not support that idea at all. It never tells us that angels are omniscient. And if a holy angel isn’t omniscient, neither is a fallen one. So, Satan can’t read our thoughts, even if he’s great at predicting human behavior because he’s seen so much of it.
I was speaking at a conference in Iowa about this problem. People were asking questions like “How do you deal with demons?” and “Do we need exorcism to get rid of demons?” Well, there are a lot of people today who say you do. I once read a book about deliverance in which the author described a doctor who was supposedly delivered from the demon of post-nasal drip. And in this approach, whenever you think you have a demon, there’s a certain magical formula you say or you run around or “plead the blood”—whatever that phrase means, since it’s not from the Scripture. The blood has already been plead in your behalf at the time of your salvation and that takes care of it. . .[continue reading]