Demons are evil spirits which follow the will of their prince, Satan (Matthew 12:24; Ephesians 2:2). The Bible does not explain how they came to be, except to say that God is the creator of all things originally, both spiritual and physical, and that he created everything good in the beginning (Colossians 1:16; Genesis 1:31). According to the Old Testament, the idolatry which was so vehemently condemned by God in the Old Testament, involved the worship of demons (Deuteronomy 32:17; Psalm 106:37; 1 Corinthians 10:20-22). Demons are evil spiritual beings with an influence over many people.
In the ministry of Jesus, we encounter the idea of demon possession as Jesus does battle with the forces of Satan and drives them out before him like a conqueror. The most indepth story of demonic possession and exorcism is the story of the Gardarene demoniac (Matthew 8:28-34; Mark 5:1-20). In this case, a man who was super strong and super violent and very self-destructive in his behavior came to Jesus and fell down in front of him. His voice cried out, “What do you want with me Jesus, Son of the Most High God? Swear that you won’t torture me!” Jesus replied, “Come out of this man you evil spirit!” Then Jesus asked the demon, “What is your name?” “My name is Legion, for we are many,” he replied. As the story goes on, Jesus drives the demons out of the man after which they enter a herd of pigs which then go running over a cliff and drown in the sea. In this account, the demons caused horrible self destructive behavior which was also dangerous to others. The demons spoke using the man’s body and the man’s voice. However, the fact that the man came to Jesus and fell down before him, suggests to me that the demon possessed man still had some of his own free will. He wanted to be rid of the demons. Jesus freed him from the demons. Then, when the man was clothed and in his right mind, Jesus told him, “Go home to your family and tell them how much the Lord has done for you, and how he has had mercy on you!” (Mark 5:19). The demons had great power over this man but could not stop him from coming to Jesus.
In Matthew 12:22ff Jesus cast a demon out of a man who was blind and mute. When the demon had been cast out, the man could both see and talk. The demon’s presence, then, seems to have been related to the physical maladies of the man. On another occasion, a demon caused a man to convulse violently (Mark 1:25). Another man, whose son was possessed by a demon, foamed at the mouth, knashed his teeth, and became rigid. The demon would often throw the child into the fire or into the water to attempt to kill him. The disciples could not cast this demon out. Jesus told the father that everything is possible for the one who believes. The man’s reply is classic, “I believe! Help me overcome my unbelief!” Jesus, of course, drove out the demon, but the disciples wanted to know why they were unable to cast it out? Jesus replied, “This kind can come out only by prayer,” (Mark 9:29). Some manuscripts read “This kind can come out only by prayer and fasting.” This seems to imply that some demons are stronger and more resistant than others.
Jesus’ campaign of casting out the demons was about binding the strong man so Jesus could rob his house (Matthew 12:29). He was conquering Satan’s territory during his ministry and the decisive battle against Satan was won at the cross. But somehow, after the cross, there was still demon possession.
Philip the evangelist drove the evil spirits out of the Samaritans (Acts 8:6-8). Paul and Silas cast the evil spirit out of the slave girl at Philippi (Acts 16:16-19). There is the strange story of the demon-possessed man who attacked and beat up the seven sons of the Jewish chief priest, Sceva, so that they ran from the house naked and bleeding. These Jewish men had tried to exorcise the demons and the demons had said, “Jesus I know, and I know about Paul, but who are you?” (Acts 19:15). Jesus told his disciples, “These signs shall follow them that believe . . . in my name they will cast out demons . . .,” (Mark 16:17).
For the Christian who has been delivered out of the power of darkness and translated into the kingdom of his beloved Son, the armor of God is the answer to our daily battle with the demonic powers (Colossians 1:13; Ephesians 6:10-18).