Gospel of John
Biblical text used against Demons. Although the reading of any Scripture sends a possessing Demon into a tailspin, the words in the Gospel of John seem to cause the most discomfort. The beginning of the book, especially, sent medieval Demoniacs into howling fits and tantrums. The following text appears in the King James version, much as 16th- and 17th-century exorcists would have read it:
In the beginning was the Word, and the Word was with God, and the Word was God. The same was in the beginning with God. All things were made by him; and without him was not any thing made that was made. In him was life; and the life was the light of men. And the light shineth in darkness; and the darkness comprehended it not.
John 1:1–5
And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotton of the Father), full of grace and truth.
John 1:14
If all things are made by God, then the Devil is also God’s instrument, perhaps sent to test humans’ faith. But can the Devil’s claims and boasts be believed? In chapter 8, John tells that Jesus rebuked the Pharisees for not believing in him or his works, saying:
If God were your Father, ye would love me; for I proceeded forth and came from God; neither came I of myself, but he sent me. Why do ye not understand my speech? even because ye cannot hear my word. Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own; for he is a liar, and the father of it.
John 8:42–44
The reasoning that any words spoken by the Devil were lies acted as a defense for many witches against their accusers. Claims that some poor soul had caused another to be possessed were looked on skeptically by early church inquisitors but not by later ones. Yet Catholic and Protestant exorcists alike believe in the ultimate power of God’s word over the work of the Devil; he may be the “father of lies,” but when confronted in the name of the Lord, the Devil is forced to yield and speak the truth.

The Encyclopedia of Demons and Demonology – Written by Rosemary Ellen Guiley – Copyright © 2009 by Visionary Living, Inc.