In ancient times many people believed that an evil spirit could enter a person's body and take control of it. This was a common explanation for afflictions such as epilepsy and madness. In modern terminology this "madness" probably referred to various mental disorders such as schizophrenia and delirium. Even today, we still don't fully understand what causes these conditions. Because ancient people had even less understanding, they frequently put the blame on evil spirits.
These evil spirits were also called demons, devils, or unclean spirits. Anyone who came under their control was called a demoniac (or daimoniac), and the condition was known as "demonic possession".
The traditional remedy for demonic possession is to expel the evil spirit from the afflicted person's body. In ancient times this was known as driving out (or casting out) the demon. Many people in modern societies call it exorcism, and use the name exorcist for anyone who can successfully do it.
According to Mark 1:23-26, the first public miracle of Jesus was an exorcism. He was teaching in a synagogue when a man "who was possessed by an evil spirit" cried out:
"What do you want with us, Jesus of Nazareth? Have you come to destroy us? I know who you are -- the Holy One of God."
"Be quiet!" Jesus said sternly. "Come out of him!" The evil spirit shook the man violently and came out of him with a shriek.
In this passage the voice of the man is actually the voice of the demon inside him controlling his vocal chords. And because this demon is a spirit, it is able to recognize Jesus as "the Holy One of God." But Jesus tells it to "Be quiet" about this. At this stage of his ministry he was trying to keep his messiahship secret, and he didn't want the demon to reveal it publicly.
The demon also asks Jesus if he has come to "destroy us." When it says "us", it is referring to itself and all the other demons in the world. It is afraid that Jesus has come to destroy all of them. This is an example of one of the main themes in the Gospel of Mark, which depicts Jesus as waging a kind of war against demons. But since demons were regarded as agents of the Devil, this was actually a war between Christ and Satan.
According to witnesses to modern exorcisms, the demon sometimes tries to hide within the victim, and hours can pass before it is finally forced to reveal itself. Then a prolonged struggle will often take place, with the victim shaking and jerking violently as the demon fights the spiritual powers invoked to expel it. During one reported struggle of this type, the victim's face suddenly contorted into an evil sneer that apparently emanated from the demon itself. Then a terrifying shriek pierced the air, and the body collapsed on the floor as the demon left it.
Some attempted exorcisms have had tragic endings. In these cases, victims were tied down, then choked, squeezed, beaten, and/or starved, and this eventually caused them to die. As a result of these deaths, several exorcists have been convicted of criminal offenses and sent to prison.
Jesus never used physical force when he performed an exorcism. He simply ordered the demon to leave the body. Acts 16:16-18 describes a case in which Saint Paul also expelled a demon by a simple command.
Although most cases of possession involve a single evil spirit, it's possible for a person to be taken over by several of them simultaneously. For example, Luke 8:2 says that seven demons had been expelled from Mary Magdalene. In a modern case, a victim spoke in different voices which claimed to be the same demons that in the past had possessed Judas Iscariot, Emperor Nero, Adolf Hitler, and several other evil people.
Unfortunately, Christians have sometimes accused other Christians of being possessed by demons. This has happened during religious wars and persecutions, and during investigations into heresy and witchcraft. At the trial of Joan of Arc, church authorities said that the voices in her head came from demons. In modern times accusations of demon possession have been made against members of certain fringe sects and against people who speak in tongues.
John 7:20 says that some people in Jerusalem even accused Jesus himself of being possessed by a demon. This may have been their explanation for his ability to perform miraculous cures. At that time there was a general belief that a possessed person could have unusual qualities such as superhuman strength, ability to see the future, or other special powers.
Evil spirits are sometimes blamed for other problems besides epilepsy and madness. For example, some people say that alcoholics, homosexuals, drug addicts, sexual predators, and adulterers are possessed by demons. Members of some church groups believe that a person who is filled with the Holy Spirit will be protected from the demons that cause these types of problems.
Demonic possession has some similarities to multiple personality disorder. In this comparison, the "demon" is an evil alternate personality that can temporarily take control of the mind. Even when this other personality isn't in full control, but is merely lurking within the person's subconscious, it still might be able to influence behavior. Some people use this idea to try to blame their evil actions on an "inner demon".
According to some ancient sources, demons were originally angels in heaven who supported the Devil in his rebellion against God, and were thrown out of heaven with him. Some sources say that one-third of the angels were thrown out in this way, and this has led to estimates that thousands, or even millions, of demons now serve Satan here on the earth.
But many people doubt that demons really exist. In their view, the possessed individuals described in the gospels were simply people who had mental illnesses. And Jesus cured them either through miracles or by using psychological techniques such as hypnosis.
Note: For more details on this topic, go to this article about Demonic Possession
