c. 391 · John Chrysostom, Homilies on the Gospel of John 16.4
Well hath a wise man said, “The beginning of pride is not to know the Lord.” The devil would not have been brought down and become a devil, not being a devil before, had he not been sick of this disease. This it was that cast him out from that confidence, this sent him to the pit of fire, this was the cause of all his woes. For it is enough of itself to destroy every excellence of the soul, whether it find almsgiving, or prayer, or fasting, or anything. For, saith the Evangelist, “That which is highly esteemed among men is impure before the Lord.” ( Luke xvi. 15 —not quoted exactly.) Therefore it is not only fornication or adultery that are wont to defile those who practice them, but pride also, and that far more than those vices. Why? Because fornication though it is an unpardonable sin, yet a man may plead the desire; but pride cannot possibly find any cause or pretext of any sort whatever by which to obtain so much as a shadow of excuse; it is nothing but a distortion and most grievous disease of the soul, produced from no other source but folly. For there is nothing more foolish than a proud man, though he be surrounded with wealth, though he possess much of the wisdom of this world, though he be set in royal place, though he bear about with all things that among men appear desirable.