We may safely conclude that Satan does not know the thoughts of man as God does. But still, as Satan is a spirit, he has a freer and more frequent intercourse with the human mind than many are aware of. I look at the mind as the spring, and thoughts as the streams issuing from it. Satan cannot exactly see or discern the spring head, nor perhaps all the streams. A good man may have many thoughts which Satan cannot be very privy to. I think that in the exercise of faith, love, hope, etc., thoughts must be employed as the mind is enlightened by the Holy Spirit.