Satan is a fallen creature and he does not possess either omniscience or omnipotence. John 8:4444Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it. (John 8:44) is a distinct testimony. Many Christians believe that Satan is represented under the figure of the king of Tyrus, in Eze. 28:1717Thine heart was lifted up because of thy beauty, thou hast corrupted thy wisdom by reason of thy brightness: I will cast thee to the ground, I will lay thee before kings, that they may behold thee. (Ezekiel 28:17), and I think they are right. But Satan has a whole multitude of demons under his authority—so much so that in the poor Gadarene there was a legion. He is the prince of demons.
With respect to the knowledge of thoughts, he does not know them intuitively, as God does; but he knows as ' a spirit full of intelligence and subtlety, who discerns with the greatest clearness the motives of the heart, and who has gained experience by the practice of many thousand years; but I believe that he understands nothing of the power of love. He was able in his malice to raise up the Chaldeans, etc., through the desire of plunder, against Job; but, not in any way knowing the purpose of God to bless him by this means, he did nothing but fulfill it. He did all that he could to get Christ put to death, but he only fulfilled the wonderful purpose of God for our salvation.
However, when he has to do with the evil heart of man, the case is different. He can present objects to awaken lusts. If we reckon ourselves to be dead, dead to sin, and alive unto God through Jesus Christ our Lord, he is not able to tempt us; at least, the temptation remains without effect. But if the flesh is not held as dead, then he can present objects which the flesh likes, and suggest to a man the means of satisfying his lusts. Thus he put it into the heart of Judas to betray Jesus for a little money. But man is responsible, because without lust Satan could do nothing; he has nothing to offer to the new man, or if he offers anything, it only produces horror in the soul; the soul suffers as Christ suffered at the sight of evil in this world, or else it overcomes as Christ overcame in the wilderness.
But when the soul is set free, he can indeed insinuate wicked thoughts, and unbelieving thoughts, and words of blasphemy, in such a way that these words and thoughts seem to proceed from the man himself. Nevertheless, if the man is truly converted, we always find that he has a sense of horror at the things that arise in his mind, and we see that they are not really his own thoughts. If he is not converted, he does not distinguish between the demon and himself, as we find in the gospels. But also when he is converted, it is a proof that he has opened the door to the devil by sin—hidden sin it may be—or by negligence.
Further, Satan is the prince of this world, and its god, and he governs the world by means of the passions and lusts of men; and he is able to raise up the whole world against Christians, as he did against Christ, and so try their faith. He can seek to mingle truth and error, and thus deceive Christians if they are not spiritual. He can, as did the demon at Philippi, get Christians mixed up with the world in order to destroy the testimony of God; he can change himself into an angel of light, but the spiritual man discerns all things (1 Cor. 2:1515But he that is spiritual judgeth all things, yet he himself is judged of no man. (1 Corinthians 2:15); J.N.D. Trans.). Satan has little power over us if we walk humbly, close to the Lord, following faithfully the Word of God, having Christ as the only Object of the heart. Satan knows well that he has been conquered; therefore it is said, "Resist the devil, and he will flee from you." His influence in the world is very great through the motives of the human heart, and he acts on men through each other; likewise, from the rapidity of his operations and actions, he appears to be everywhere; and then he employs a great multitude of servants who are all wicked. But in fact he is not present everywhere. Now God is really present, and if we are under the influence of the Spirit of God, and the conscience is in the presence of God, Satan has no power. "He that is begotten of God keepeth himself, and that wicked one toucheth him not." However things may be with us, if we are truly the children of God, he will fulfill the counsels of God with respect to us; it may be, if need be, by chastisement. But God knows all things; He in the most absolute sense penetrates everywhere. He orders all things—Satan's efforts even—for our good. If we are armed with the whole armor of God, the darts of the evil one do not reach the soul.