A good deal of skepticism has been expressed about Satan. Those who take the Bible seriously are obliged to believe in Satan’s existence, since the Bible unmistakably refers to the demonic. Nonetheless, it is objected by skeptics and atheists that belief in a sinister evil power in the universe is outmoded and superstitious.

A real personal Devil is given distinctive traits of personality, including intellect (2 Cor. 11:3; Luke 4: 1f.). Ascribed to him are the emotions of desire (1 Tim. 3:6; cf. Isa. 14:12f.), jealousy (Job 1:8, 9), hatred (1 Peter 4:8), anger (Rev. 12:12), and will. The Devil commands (Luke 4:3, 9) and leads rebellions (Rev. 12:1-3).

Some evidence for the personality and reality of Satan is direct. In total, it is sufficient to establish existence of a personal Devil.

Once the authenticity and Divine Origin of the Bible are established, the existence of Satan follows.

Genesis 3:1 describes Satan as a personal enemy of God and humans who deceives: "Indeed, has God said, ‘You shall not eat from any tree of the garden?"’ The historicity of this passage is confirmed by New Testament references to the historicity of Adam and Eve and their fall (cf. Rom. 5:12; 1 Tim. 2:13-14).

First Chronicles 21:1 and Psalm 109:6 describe Satan as standing against God’s people. Job 1-2 records that Satan has access to God’s presence and accuses people: "Now there was a day when the sons of God came to present themselves before the Lord, and Satan also came among them" (1:6). Satan is the real cause of Job’s otherwise unexplainable suffering.

Nineteen of the twenty-seven New Testament books refer to Satan (and four more to demons). We gain a lot more informed understanding of this sphere of rebellion against God. The personal encounters and conversations of Christ with Satan and demons made it evident that Jesus believed in a real, personal Satan. Jesus made twenty-five of the twenty-nine references to Satan found in the Gospels. Indeed, Jesus carried on an extended conversation with Satan during his temptation. Matthew 4 and Luke 4 describe a personal encounter between Satan and Jesus. Mark 1:12 and Hebrews 4:13 refer to this confrontation. To deny the reality of a personal Satan in these passages is to impugn the integrity or sanity of Christ. In Revelation 12:9 several names describing Satan are mentioned in one passage: "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." Rev. 20:2 speaks of an angel of God who "laid hold of the dragon, the serpent of old, who is the devil and Satan, and bound him for a thousand years.

The events surrounding the temptation are all historical—the ministry of John the Baptist and baptism of Jesus (cf. Matthew 3). The nature and reality of the account is too vivid to be merely symbolic. The Gospels accord considerable significance to the event as a watershed point in the life of Christ and salvation history. He declared himself to be the Son of God; he conquered temptation. He passed the test the first Adam had failed.

The history of both Israel and the church are difficult to understand apart from a personal Satan who seeks to thwart God’s plan for history. At the fall it was announced that human salvation would come through the promised seed of the woman (Gen. 3:15). This covenant promise was eventually narrowed to the offspring of Abraham through Isaac and Jacob (Gen. 12:1-3; 36; 46). The covenant came to be centered in twelve tribes of Israel (Genesis 49). Satan relentlessly attacked that bloodline (cf. Num. 24:10; Zech 3:1).

Considering the relative insignificance of Israel in the history of the world, they have been the continual, repeated victims of programs of genocide, starting with the Persians (cf. Esther). The Greek conquest of Palestine was a studied attempt to destroy the Jewish culture with few parallels. From Haman through medieval pogroms to Hitler, Stalinization, and Sadam Hussain, this tiny people have been targeted. This conspiracy of hatred against the Jews is best explained as emanating from one sinister evil mind. This is to say nothing of the two millennia of attacks on Christian identity, purity, and community. On numerous occasions these attacks have seemed perilously close to demolishing God’s new covenant people.

Another argument in support of the reality of the Devil is that of demons who express a unified conspiracy against God, his plan, and his people. Without a leader the demonic forces would not manifest such an organized show of force against God. Indeed, the Bible describes Satan as their prince (Luke 11:15) and "king" (Rev. 9:11). The increasing evidence for true demonic possession is an extrabiblical source of support for the reality of demons.

Another evidence of the reality of a personal Devil is the universal, powerful and persistent nature of the temptation to do evil. What else accounts for heinous crimes committed by seemingly decent people, from David to the present. Even law-abiding people (who pass for what we call "good") show that they are not good by feeling the urge to do things totally out of keeping with their character. And this includes Christians. The universal temptation to sin, even by godly people, is best explained by a sustained, personal attack. Evil does not fit the impersonal force category under which it is often placed. Gravity and magnetism are impersonal forces, but they do not personally allure. Evil by its very nature interacts with intellect and will.

The existence of thousands of false religions and cults testifies to the existence of a great Deceiver. Paul wrote: "The Spirit clearly says that in latter times some will abandon the faith and follow deceiving spirits and things taught by demons. Such teachings come through hypocritical liars, whose consciences have been seared as with a hot iron (1 Tim. 4:1-2).

Considered as a whole the direct and indirect evidence for the existence of a personal evil power behind this world is substantial. It is based both in history and in personal experience.

A common objection to the existence of the demonic is that there are natural explanations for what is sometimes called "demonic" or evil. A common argument is that sicknesses once attributed to the demonic, even by the Bible, are now known to have natural causes. This objection overlooks that the Bible distinguishes between sickness and demonic possession. Jesus differentiated between them when he listed them as separate miracles the apostles were given power to do: "Heal the sick, raise the dead, cleanse those who have leprosy, drive out demons" (Matt. 10:8). The Bible does not claim that all sickness is demonically caused. The Bible recommends the use of medicine in treating natural sickness (cf. 1 Tim. 5:23).

Similar symptoms may be present in sicknesses and some demon possessions, but that does not prove there is a natural explanation for both. The young man from whom a demon was cast in Matthew 17:14-17 had symptoms similar to those of an epileptic seizure, but that doesn’t mean he had epilepsy. Similar effects do not prove identical causes. Both God and the magicians of Egypt turned water blood-red. Even a demon-caused illness might respond to medicine. Many induced sicknesses can be treated. Because a mind caused it (whether human or demonic) does not mean medicine cannot relieve symptoms.

At least some demonic activity manifests distinctive spiritual characteristics not present with natural sickness. These symptoms could include such things as opposition to God, violent reaction to Christ, and the manifestation of supernormal strength (cf. Mark 5: 1-4). These do not respond to any purely natural treatment.

Another argument is that belief in satanic activity is characteristic among the uneducated. These beliefs diminish as a society moves to a modern culture. However this may partly be due to different strategies Satan uses among different peoples. He can adapt to the culture he is deceiving. What better way to deceive the sophisticated anti-supernaturalists than to lead them to believe he does not exist. The Bible declares that Satan disguises himself as an angel of light (2 Cor. 11:14). But it is not true that demonic manifestations occur only among "primitive" people. With the "post-Christian age" the Western world has seen far more occultic activity and reports of demonic manifestations.

Some of the greatest Western minds have believed in Satan and the demons. This includes Augustine, Anselm, Thomas Aquinas, Blaise Pascal, Soren Kierkegaard, and C. S. Lewis. It is not the degree of intelligence or education that determines whether one believes in a personal Satan. Rather it depends on whether one has rejected the supernatural revelation of Scripture.

M. Unger, Demonology