Chapter XVII.—The Gospel Gives Power Over Demons.
“You see, then, how important is the acknowledgment of God, and the observance of the divine religion, which not only protects those who believe from the assaults of the demon, but also gives them command over those who rule over others. And therefore it is necessary for you, who are of the Gentiles, to betake yourselves to God, and to keep yourselves from all uncleanness, that the demons may be expelled, and God may dwell in you. And at the same time, by prayers, commit yourselves to God, and call for His aid against the impudence of the demons; for whatever things ye ask, believing, ye shall receive. 736 But even the demons themselves, in proportion as they see faith grow in a man, in that proportion they depart from him, residing only in that part in which something of infidelity still remains; but from those who believe with full faith, they depart without any delay. For when a soul has come to the faith of God, it obtains the virtue of heavenly water, by which it extinguishes the demon like a spark of fire.
Matt. xxi. 22.