Evil spirits are angels driven from the presence of God. The book of Revelation tells of a great dragon, that old serpent, called the Devil, or Satan, who deceives the whole world. He was cast down to the earth. The expulsion of Satan is symbolically described in the books of Isaiah and Ezekiel. When Satan was cast out of heaven, he took a third of the angels with him. These were angels who sinned. Therefore, according to the Bible, the evil spirits are the same angels who rebelled against God with Satan.