Although it is not directly stated nevertheless we believe that it is indeed possible not only for God, but likewise for angels and yes even Satan himself to read our thoughts.
We have no real conception as to the true capabilities of spiritual beings, save that we know that they possess powers greater and higher than humanity. The only thing we know for certain is that they are invisible to human sight unless they choose to materialize in some form or fashion. From what the scriptures reveal they can materialize as both animate and inanimate objects (viz. as humans, animals or a burning bush).
Although at the present time the fallen spirits (demons) are restrained from this capacity, viz. materialization we believe this will shortly change as the time for their final judgment (krima) comes to fruition and they are freed from their chains.
Our Lord informs us that spirit beings can “come and go as the wind” (John 3:8). Even as the wind is invisible to the eye and yet we feel its presence we still know not where it comes nor where it goes, so too in regards to spirit beings.
In regards to the “ministering spirits” which minister to the saints (Matt 18:10) our Lord states, “Take heed that ye despise not one of these little ones; for I say unto you, that in heaven their angels do always behold the face (i.e. they have access to or immediate communication with) my Father which is in heaven,” this can imply one or more things either they are able to travel at the speed of thought or they have the power of telepathic communication with the Father.
“The devil can read our thoughts and so knows what temptations to put before us, even so it was with regards to our Lord when he was led by the spirit into the wilderness to be tempted by the devil.
Jesus was thinking about the work He was to do; of the miracles He would perform, and other features of the work and as he thought upon that work, the Adversary reading his thoughts said to himself, “I see now how I can get Him; He has been thinking over what He is going to do; I guess by this time He will be puffed up a little; I will try to get Him to use His power in a selfish way."
And so he suggested three shortcuts to accomplish his ends without the necessity of dying. Having experienced hunger as a result of his forty-day fast, he could turn stones into bread and solve the breadlines of the world (Matt. 4:3, 4). Or, he could win the support of the populace through some miraculous act (Matt. 4:5-7). Or, he could cooperate with the powers that be and negotiate his kingdom with the god of this world (Matt. 4:8-10). Jesus however resisted all three of these temptations with a quotation from his Father's word, It is written, and the devil fled from him (Matt. 4:11).
So the devil tempts us. He reads our hearts and our minds and sees what thoughts we are entertaining. Then he says, “I see now where he is weak; I can trip him up now." You ever wonder how it is that temptations come so subtly. If the devil could not read our thoughts he would be working in the dark, he wouldn’t know precisely how to attack us. He would be putting temptations before us which would mean nothing to us, for not all are tempted by the same things.
We should not be surprised if we could look into the devil's office we would find a list of the lines along which he could attack us; you would find in his notes under your name what you had been in the habit of thinking about, where you are weak, so that when the opportunity came to put a certain kind of temptation before you, you would probably be caught off guard by that kind of bait. Let us be careful, whenever anything unholy contrary to the will of God suggests itself, that we do not think (dwell) on these things. Resist such thoughts; put them down. "Whatsoever things are of good report, think on these things."
Satan is able to read our thoughts, but if he be able to read our thoughts, we think there is a limitation, and he is not able to inject his thoughts. We thank God for that, but we do think he is very ready to take advantage of any little slip that we may make, or opportunity we might give to intrude upon our minds.
It will not at all surprise us if these evil spirits have much more power in the near future, but we need have no fear, for "greater is he that is for us than all that be against us”.
The world (as well as the professing church) is in ignorance on the matter, and the whole world is therefore in a condition to he led captive by Satan at his will.
I must wholeheartedly disagree here Harvest.
"I the LORD search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings." Jeremiah 17:10
"then hear in heaven your dwelling place and forgive and act and render to each whose heart you know, according to all his ways (for you, you only, know the hearts of all the children of mankind)" 1 Kings 8:39.
Satan uses his minions to do his reconnaissance..he watches our every action and hears our every spoken word...not hard at all to see peoples weak spots.
The word “mind” could be used interchangeably in these verses, for they come from the same Hebrew word meaning “the heart.”
Satan’s powers are not equal to God’s. He is a created being, and limited in power. God has no equal.
There are so many verses about the Lord knowing our thoughts but, I cannot find one single one stating that Satan can.
And, IMHO-only God Almighty can do this"
“For the word of God is living and active and sharper than any two-edged sword, and piercing as far as the division of soul and spirit, of both joints and marrow, and able to judge the thoughts and intentions of the heart”
Hebrews 4:12