By Ellen G. White
Satan often finds a powerful agency for evil in the power which one human mind is capable of exerting on another human mind. This influence is so seductive that the person who is being molded by it is often unconscious of its power. God has bidden me speak warning against this evil, that His servants may not come under the deceptive power of Satan. The enemy is a master worker, and if God's people are not constantly led by the Spirit of God, they will be snared and taken. 1NL 17.1
For thousands of years Satan has been experimenting upon the properties of the human mind, and he has learned to know it well. By his subtle workings in these last days, he is linking the human mind with his own, imbuing it with his thoughts; and he is doing this work in so deceptive a manner that those who accept his guidance know not that they are being led by him at his will: The great deceiver hopes so to confuse the minds of men and women, that none but his voice will be heard. 1NL 17.2
When Christ revealed to Peter the time of trial and suffering that was just before Him, and Peter replied, “Be it far from Thee, Lord: this shall not be unto Thee,” the Saviour commanded, “Get thee behind Me, Satan.” Satan was speaking through Peter, making him act the part of the tempter. Satan's presence was unsuspected by Peter, but Christ could detect the presence of the deceiver, and in His rebuke to Peter He addressed the real foe. 1NL 17.3
On one occasion, speaking to the twelve, and referring to Judas, Christ declared, “One of you is a devil.” Often in the days of His earthly ministry the Saviour met His adversary in human form, when Satan as an unclean spirit took possession of men. Satan takes possession of the minds of men today. In my labors in the cause of God, I have again and again met those who have been thus possessed, and in the name of the Lord I have rebuked the evil spirit. 1NL 17.4
It is not by force that Satan takes possession of the human mind. While men sleep, the enemy sows tares in the church. While men are spiritually sleeping, the enemy accomplishes his work of iniquity. It is when his subject “understandeth it not” that he catcheth away the good seed sown in the heart. When men and women are in this condition, when their spiritual life is not being constantly fed by the Spirit of God, Satan can imbue them with his spirit, and lead them to work his works.... 1NL 17.5
I entreat that there may be a putting away from the life every action which does not bear the approval of God. We are drawing near to the close of earth's history; the battle is growing daily more fierce. There is a day appointed when men who have bowed to the mandates of Satan will find themselves the subjects of the wrath of God, when the Judge of all the earth shall pronounce the sentence against Satan and his adherents, “Depart from Me, ye cursed, into everlasting fire, prepared for the devil and his angels.”—Letter 244, 1907. 1NL 17.6