No, Satan CANNOT read our minds, for he is NOT omniscient (i.e. all-knowing). Only God can read minds and thus King David wrote the following in Psalm 139:1-2, “You know my sitting down and my rising up; You UNDERSTAND MY THOUGHT afar off.” He went on to say in verses 3-4, “You comprehend my path and my lying down, are acquainted with all my way. For there is not a word on my tongue, but behold, O LORD, You KNOW IT ALTOGETHER.” Satan, who was once God’s most powerful and wisest angel (name Lucifer), aspired to have this knowledge along with every other attribute of God. In Isaiah 14:12-14 we read of his rebellion and fall and in verse 14 the said, “I will ascend above the heights of the clouds, I WILL BE LIKE THE MOST HIGH.” In the next verse we read this, “Yet you shall be brought down to Sheol, to the lowest depths of the Pit.” This speaks of God’s eventual judgment upon Satan when he will be “cast into the lake of fire” (see Matthew 25:41 with Revelation 20:10). Until then, Satan is still free to roam the earth and try to exert his influence over men (see Ephesians 2:1-2), but he is not able to “read our thoughts.”

Having said that, Satan is a “keen observer” and by our actions he is able to “guess what we may be thinking.” And because of this, he can tempt mankind when he knows what their habits and weaknesses are. Judas Iscariot illustrates this for Satan knew that he was a covetous man and a thief (see John 12:4-6) and later we read, in John 13:2, “And supper being ended, the devil having already put it into the heart of Judas Iscariot, Simon’s son, to betray him.” Satan knew that he was stealing money from the money box and he was then able to “sow the thought” of betraying the Lord into his heart. It is clear from this that Satan can’t “read our minds” but he can “put evil thoughts into them.” Some commentators believe that Satan’s ability to “put thoughts into our minds” is what is being spoken of in Ephesians 6:16, “above all, taking the shield of faith with which you will be able to QUENCH ALL THE FIERY DARTS OF THE WICKED ONE.” When Satan does try to “sow his evil thoughts into our minds and hearts” we can use the “shield of faith to deflect them.” Earlier, in verse 13, we are told to “Put on the whole armor of God, that you may be able to stand against the wiles of the devil,” and one of his greatest wiles (cunning devices) is to introduce “false teachings into our minds” and unless we have “the shield of faith” (faith in God’s Word), we will be vulnerable to his attacks.

I will close by quoting another passage which speaks of the spiritual warfare we are in and how the enemy seeks to attack our minds with false teaching. “For though we walk in the flesh, we do not war according to the flesh. For the weapons of our warfare are not carnal but mighty for pulling down strongholds, casting down arguments and every high thing that exalts itself against the knowledge of God, BRINGING EVERY THOUGHT INTO CAPTIVITY TO THE OBEDIENCE OF CHRIST” (2 Corinthians 10:3-5). Satan will use the “false reasonings of men” (professors in ungodly universities, scientists who teach evolution, religious leaders with false teachings, etc.) to inject his poison into our minds. But if we hold fast to the truth of God’s precious Word, our minds and thoughts will be filled with the knowledge of God allowing us to defeat the enemy and to “bring every thought into captivity to the obedience of Christ.” This means the believer’s thoughts would be in line with God’s thoughts and obedience to the Word would result, but it may also include “the thoughts of the false teacher may be changed and persuaded of the truth, resulting in his conversion to Christ.”  (DO)  (664.5)