Revelation 12:9 - Matthew Poole's English Annotations on the Holy Bible

And the great dragon was cast out; the dragon mentioned Revelation 12:3, which typified the pagan emperors. In casting them out, the devil who influenced them, was cast out, who is here called the old serpent, with reference to the form in which he seduced Eve, as well as his malignity to man. The devil, that is, the accuser of the brethren, (of which we have an instance in Job 1:1-22), and Satan, which name he hath from his opposition to Christ and all Christians. Which deceiveth the whole world; by seducing them to idolatry and superstition. He was cast out into the earth; cast down from his former state. And his angels were cast out with him; the instruments he used in persecuting the church, were put out of power. Mr. Mede understands it of the demons which the heathens worshipped as inferior gods. John, being in his trance still, thought he saw a great red dragon, (which he judged to be the devil), and Christ, or the good angels, fighting with and overcoming him; and that he saw the devil, and those evil angels assisting him, thrown down to the earth. This prophetically and typically signified; that though the Roman emperors, being pagans, should persecute the church upwards of three hundred years, yet they should be overthrown, and paganism, with all its idolatry and superstition, should be rooted out; which occasioned a great deal of glory to God from the praises and thanksgivings of his people, expressed in the next three verses.