We do not know precisely how much Satan knows or does not know of what we are thinking. Scientists have shown that electrical current is generated by the human brain. According to at least one source I read, this current takes on the transmission qualities of radio signals. This explains, in some measure, why people who are very close often know what each other is thinking without spoken words being exchanged. For this reason, it is possible that Satan knows at least a little bit about what we are thinking.
It would seem, also, that satanic forces are aware of blessings and opportunities that lie before believers. It seems that demonic forces do everything they can to discourage the Christian just at the moment of blessing. That has happened repeatedly in my life. Just before some great blessing comes, a time of maximum attack or discouragement seems to occur.
We do not know how well-informed, intelligent, or powerful Satan and his demons are. We understand something of their abilities, but we cannot be too definitive. What we do know is that as believers, we have authority over Satan and his entire army. We also learn that God has placed a hedge of protection around us (see Job 1:10). We have the ability to attack and defeat Satan while being defended by God against Satan.
