The fact that men have been possessed with demons, is clearly stated in the New Testament. The persons thus afflicted were not merely suffering with disease from natural causes. Christ had perfect understanding of that with which He was dealing, and He recognized the direct presence and agency of evil spirits. (GC 514.1) MC VC

A striking example of their number, power, and malignity, and also of the power and mercy of Christ, is given in the Scripture account of the healing of the demoniacs at Gadara. Those wretched maniacs, spurning all restraint, writhing, foaming, raging, were filling the air with their cries, doing violence to themselves, and endangering all who should approach them. Their bleeding and disfigured bodies and distracted minds presented a spectacle well pleasing to the prince of darkness. One of the demons controlling the sufferers declared: “My name is Legion: for we are many.” Mark 5:9. In the Roman army a legion consisted of from three to five thousand men. Satan’s hosts also are marshaled in companies, and the single company to which these demons belonged numbered no less than a legion. (GC 514.2) MC VC

At the command of Jesus the evil spirits departed from their victims, leaving them calmly sitting at the Saviour’s feet, subdued, intelligent, and gentle. But the demons were permitted to sweep a herd of swine into the sea; and to the dwellers of Gadara the loss of these outweighed the blessings which Christ had bestowed, and the divine Healer was entreated to depart. This was the result which Satan designed to secure. By casting the blame of their loss upon Jesus, he aroused the selfish fears of the people and prevented them from listening to His words. Satan is constantly accusing Christians as the cause of loss, misfortune, and suffering, instead of allowing the reproach to fall where it belongs—upon himself and his agents. (GC 514.3) MC VC