ANSWER: Unlike the devil, the Bible clearly informs us that Jesus Christ could read the minds of others. In the book of Matthew he directly states he has this power when he says, "But Jesus, perceiving their thoughts, said, 'Why are you thinking evil in your hearts?'" (Matthew 9, see also Luke 9:47).
The word of God reads and judges our thoughts and attitudes. Everything we think can be clearly seen by him. In the book of Hebrews, the apostle Paul states that God's spirit can find out all of the thoughts and desires in our hearts. Absolutely nothing is hidden from the Great God that he desires to know! This is the exact opposite of the devil whose power is greatly limited by his Creator.
The devil has not be given the power to read our minds. He does know, however, as a constant observer of humanity since Adam and Eve, what generally motivates us. He knows how humans think in general because he thinks the same way! The devil knows the weaknesses of human beings and therefore knows how to tempt us.
Jesus, toward the end of his ministry, began to openly tell the disciples that he would suffer and die in Jerusalem at the hands of Jewish religious leaders. One day Peter decided to rebuke his Master over the idea that he had to die for our sins. Jesus' correction of Peter gives us another clue as to why the devil seems to know what we are thinking.
Jesus corrected Peter by stating, "Get away from me, Satan! You are an obstacle in my way, because these thoughts of yours don't come from God, but from human nature" (Matthew 16:23). The devil seems to know our thoughts because human nature, apart from God's spirit, can easily think and reason like he does!
The devil cannot and does not know our innermost thoughts. He simply cannot read our minds, otherwise, he would not have wasted his energy trying to tempt Job (Job 1:6 - 12), or even Jesus when he was a flesh and blood human (Matthew 4:1 - 11).
The devil certainly does have the power to deceive those who do not follow God. As god of this world, he has deceived the masses regarding the truth, God's REAL plan of salvation and mankind's great and wonderful destiny.
Jesus, when He died for our sins and began to establish his kingdom, put Satan under his power and authority. The devil no longer has power over us. Through God we can assurred that he cannot read our thoughts.