Demoniac is a term used for someone who is possessed by a demon, or daemon, the Greek word for the lesser perverted angels who followed Satan in his incredibly foolish rebellion against God. Also known as "devils," it is possible for them to "possess" people who do not have the Holy Spirit of God, in much the same way that squatters can take up residence in a vacant house. Although most particularly vulnerable are those who have chosen to live a life contrary to God's Laws of morality and righteousness, demons, like the coward Satan himself, also prey upon the weak and innocent who simply have not yet been converted. Although very powerful, demons are powerless against the Holy Spirit.
The Healing of Demoniacs By Jesus Christ
Jesus Christ healed many demoniacs during His ministry.
"And He went about all Galilee, teaching in their Synagogues and preaching the Gospel of the Kingdom and healing every disease and every infirmity among the people. So His fame spread throughout all Syria, and they brought Him all the sick, those afflicted with various diseases and pains, demoniacs, epileptics, and paralytics, and He healed them." (Matthew 4:23-24 RSV)
"That evening they brought to Him many who were possessed with demons; and He cast out the spirits with a word, and healed all who were sick. This was to fulfil what was spoken by the prophet Isaiah, "He took our infirmities and bore our diseases." (Matthew 8:16-17 RSV)
"And when He came to the other side, to the country of the Gadarenes, two demoniacs met Him, coming out of the tombs, so fierce that no one could pass that way. And behold, they cried out, "What have You to do with us, O Son of God? Have You come here to torment us before the time?" Now a herd of many swine was feeding at some distance from them. And the demons begged Him, "If You cast us out, send us away into the herd of swine." And He said to them, "Go." So they came out and went into the swine; and behold, the whole herd rushed down the steep bank into the sea, and perished in the waters." (Matthew 8:28-32 RSV)
"And He said to her, "For this saying you may go your way; the demon has left your daughter." And she went home, and found the child lying in bed, and the demon gone." (Mark 7:29-30 RSV)
The Healing of Demoniacs By Those With The Holy Spirit
Jesus Christ was The Messiah, but He was also completely human; He couldn't have been crucified to death if He wasn't e.g. "Therefore He had to be made like His brethren in every respect" (Hebrews 2:17). His Power was from the Holy Spirit of God, the same Power that is given to those who are genuinely converted e.g. "Truly, truly, I say to you, he who believes in Me will also do the works that I do; and greater works than these will he do, because I go to The Father." (John 14:12 RSV)
"And preach as you go, saying, 'The kingdom of heaven is at hand.' Heal the sick, raise the dead, cleanse lepers, cast out demons." (Matthew 10:7-8 RSV)
"And if any place will not receive you and they refuse to hear you, when you leave, shake off the dust that is on your feet for a testimony against them." So they went out and preached that men should repent. And they cast out many demons, and anointed with oil many that were sick and healed them." (Mark 6:11-13 RSV)
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1 Corinthians 10:20