Augustine of Hippo : Here I see a difficulty occurring to one of limited knowledge [of Scripture], that is, why miracles are also done by magical arts, for the magicians of Pharaoh also made serpents and other similar things. But what is a much greater cause of wonder is how the power of the magicians, who could make serpents, utterly failed when it came to very small gnats. For the sciniphs, by which the proud people of Egypt were afflicted, are very small flies. And there certainly the magicians who failed, exclaimed, "This is the finger of God." We are thereby given to understand that not even the angels and the spirits of the air, who transgressed and were cast from that home of sublime and ethereal beauty into this most profound darkness, as into a prison peculiar to them, could do anything that they could by means of their magical arts, if the power had not been given to them from above. — THE TRINITY 3.7.12 Augustine of Hippo : Isn't the finger of God to be understood as being the Holy Spirit? Read the Gospel, and see that where one Evangelist has the Lord saying, "If I with the Spirit of God cast out demons," another says, "If I with the finger of God cast out demons." So if that law too was written by the finger of God, that is, by the Spirit of God, the Spirit by which Pharaoh's magicians were defeated, so they said, "This is the finger of God, … why can it not be said of it, "For the law of the Spirit of life in Christ Jesus has delivered you from the law of sin and death"? — SERMON 155.3