On The Holy Trinity by St. Augustine
Chapter 7.--Great Miracles Wrought by Magic Arts.
12. I see here what may occur to a weak judgment, namely, why such miracles are wrought also by magic arts; for the wise men of Pharaoh likewise made serpents, and did other like things. Yet it is still more a matter of wonder, how it was that the power of those magicians, which was able to make serpents, when it came to very small flies, failed altogether. For the lice, by which third plague the proud people of Egypt were smitten, are very short-lived little flies; yet there certainly the magicians failed, saying, |This is the finger of God.| And hence it is given us to understand that not even those angels and powers of the air that transgressed, who have been thrust down into that lowest darkness, as into a peculiar prison, from their habitation in that lofty ethereal purity, through whom magic arts have whatever power they have, can do anything except by power given from above. Now that power is given either to deceive the deceitful, as it was given against the Egyptians, and against the magicians also themselves, in order that in the seducing of those spirits they might seem admirable by whom they were wrought, but to be condemned by the truth of God; or for the admonishing of the faithful, lest they should desire to do anything of the kind as though it were a great thing, for which reason they have been handed down to us also by the authority of Scripture; or lastly, for the exercising, proving, and manifesting of the patience of the righteous. For it was not by any small power of visible miracles that Job lost all that he had, and both his children and his bodily health itself.