Who can hear our silent prayers -- those prayers that are thought in our minds but not verbalized? Isn't God the only one who can read our minds and hearts? Satan cannot hear our thoughts, can he?
In dedicating the temple, Solomon prayed, "whatever prayer, whatever supplication is made by anyone, or by all Your people Israel, when each one knows the plague of his own heart, and spreads out his hands toward this temple: then hear in heaven Your dwelling place, and forgive, and act, and give to everyone according to all his ways, whose heart You know (for You alone know the hearts of all the sons of men), that they may fear You all the days that they live in the land which You gave to our fathers" (I Kings 8:38-40). Therefore, only God knows our thoughts.
This becomes one evidence of the deity of Jesus. "But when Jesus perceived their thoughts, He answered and said to them, "Why are you reasoning in your hearts?"" (Luke 5:22). "But Jesus did not commit Himself to them, because He knew all men, and had no need that anyone should testify of man, for He knew what was in man" (John 2:24-25).
It is also evidence of the deity of the Holy Spirit. "Likewise the Spirit also helps in our weaknesses. For we do not know what we should pray for as we ought, but the Spirit Himself makes intercession for us with groanings which cannot be uttered" (Romans 8:26).
Because God is able to know our thoughts, He is able to give accurate judgment. "Therefore judge nothing before the time, until the Lord comes, who will both bring to light the hidden things of darkness and reveal the counsels of the hearts. Then each one's praise will come from God" (I Corinthians 4:5).
Satan, not being a deity, is unable to read our minds. That is why Satan thought he would be able to cause Job to sin and in the end, was proven wrong. "Then the LORD said to Satan, "Have you considered My servant Job, that there is none like him on the earth, a blameless and upright man, one who fears God and shuns evil?" So Satan answered the LORD and said, "Does Job fear God for nothing? Have You not made a hedge around him, around his household, and around all that he has on every side? You have blessed the work of his hands, and his possessions have increased in the land. But now, stretch out Your hand and touch all that he has, and he will surely curse You to Your face!"" (Job 1:8-11). "In all this Job did not sin nor charge God with wrong" (Job 1:22). Satan did not know the heart of Job.