Excerpt from The Life of St. Antony:

'Once a demon exceeding high appeared with pomp, and dared to say, "I am the power of God and I am Providence, what dost thou wish that I shall give thee?" But I then so much the more breathed upon him , and spoke the name of Christ, and set about to smite him. And I seemed to have smitten him, and forthwith he, big as he was, together with all his demons, disappeared at the name of Christ. At another time, while I was fasting, he came full of craft, under the semblance of a monk, with what seemed to be loaves, and gave me counsel, saying, "Eat and cease from thy many labours. Thou also art a man and art like to fall sick." But I, perceiving his device, rose up to pray; and he endured it not, for he departed, and through the door there seemed to go out as it were smoke. How often in the desert has he displayed what resembled gold, that I should only touch it and look on it. But I sang psalms against him, and he vanished away. Often they would beat me with stripes, and I repeated again and again, "Nothing shall separate me from the love of Christ ," and at this they rather fell to beating one another. Nor was it I that stayed them and destroyed their power, but it was the Lord, who said, "I beheld Satan as lightning fall from Heavens; " but I, children, mindful of the Apostle's words, transferred this to myself, that you might learn not to faint in discipline, nor to fear the devil nor the delusions of the demons.