Nicene and Post-Nicene Fathers, Ser. II, Vol. XI:
The Works of John Cassian.: Chapter XVIII. Of the degrees of wickedness which exist in hostile spirits, as shown in the case of two philosophers.

Chapter XVIII.

Of the degrees of wickedness which exist in hostile spirits, as shown in the case of two philosophers.

But of the difference that there is between demons we have learnt a great deal by means of those two philosophers who formerly by acts of magic had oftentimes great experience both of their laziness and of their courage and savage wickedness. For these looking down on the blessed Antony as a boor and rustic, and wanting, if they could not injure him any further, at least to drive him from his cell by illusions of magic and the devices of demons, despatched against him most foul spirits, for they were impelled to this attack upon him by the sting of jealousy because enormous crowds came daily to him as the servant of God. And when these most savage demons did not even venture to approach him as he was now signing his breast and forehead with the sign of the cross, and, now devoting himself to prayer and supplication, they returned without any result to those who had directed them; and these again sent against him others more desperate in wickedness, and when these too had spent their strength in vain, and returned without having accomplished anything, and others still more powerful were nevertheless told off against the victorious soldier of Christ, and could prevail nothing against him, all these great plots of theirs devised with all the arts of magic were only useful in proving the great value that there is in the profession of Christians, so that those fierce and powerful shadows, which they thought would veil the sun and moon if they were directed towards them, could not only not injure him, but not even draw him forth from his monastery for a single instant.