Demons are supernatural beings who are subservient to Satan. They, like Satan, were once angels. They joined Satan in his rebellion and were cast out of heaven with him. When they are mentioned in Scripture, the primary focus is on demon possession of human beings.
The apostle Paul points out that while the idolatrous gods pagans worship do not actually exist, there are demons who do exist, instigating and propagating such pagan worship. Those who participate in these pagan rituals are actually offering worship to demons and are thus operating under demonic direction.
The New Testament reveals several characteristics of demons. There is often a physical or mental ailment associated with them, such as blindness or self-torture. Demons often recognized Christ as the Holy One of God. They feared and were subject to the authority of Jesus. In addition, demons had superior or supernatural knowledge, superior strength, and the ability to foretell the future.
While demons still continue to act, the level and severity of activity expressed in the New Testament is unique. It was the “fullness of time,” the last great defense of this world against the Redeemer of mankind. Satan, as it were, pulled out all the stops. With the Resurrection and the coming of the Holy Spirit at Pentecost, Satan’s reign, and that of his fellow demons, was severely restricted. However, both Paul and John warn believers that in the end times the activities of Satan and his demons will be on the increase.
If we take the Bible seriously, we must take the demonic world seriously. There can be no biblical theology without a corresponding demonology.
Though demons are real and powerful, there is no reason to believe that they can ever possess a Christian. We may be harassed, tempted, or accused by demons, but never controlled by them. Every Christian is indwelt by the Holy Spirit. His presence guarantees liberty from demonic possession. He is stronger than any demon that might attack us.