Don’t underestimate the mode of operation of Satan. The enemy does plant seeds of doubt through speaking to you in your thoughts. The devil does tempt you. The dragon does show you images in your head to deceive you. The evil one does mislead you. Satan does cause you to go astray. Lucifer does speak to you and tell you lies. 
Now, do we have power over the enemy? Yes we do. Do we have a choice as to whether or not to believe Satan’s lies? Absolutely. But one of the most powerful weapons for us in our struggle against principalities is to know how the enemy operates. Yes, we have already defeated the devil but not through underestimating his craftiness. The enemy has been exposed. Go forth and win your battles today. Dr.J.

Genesis 3:1 “Now the serpent was more crafty than any of the wild animals the Lord God had made. He said to the woman, ‘Did God really say, “You must not eat from any tree in the garden”?”

John 8:44 “You are of your father the devil, and you want to do the desires of your father He was a murderer from the beginning, and does not stand in the truth because there is no truth in him Whenever he speaks a lie, he speaks from his own nature, for he is a liar and the father of lies.

Luke 4:1-3 “Jesus, full of the Holy Spirit, left the Jordan and was led by the Spirit into the wilderness, where for forty days he was tempted by the devil. He ate nothing during those days, and at the end of them he was hungry. The devil said to him, ‘If you are the Son of God, tell this stone to become bread.'”

Luke 4:5 “The devil led him up to a high place and showed him in an instant all the kingdoms of the world.”

Luke 4:9 “The devil led him to Jerusalem and had him stand on the highest point of the temple. ‘If you are the Son of God,’ he said, ‘throw yourself down from here.'”

Revelation 12:9 “And the great dragon was thrown down, the serpent of old who is called the devil and Satan, who deceives the whole world; he was thrown down to the earth, and his angels were thrown down with him.”

Matthew 24:24 “For false Christs and false prophets will appear and they will provide great signs and wonders, so as to deceive, if possible, even the elect (God’s chosen ones).”