11 Nay, more than this: from the fables they had themselves devised respecting their own deities, they deduced occasions for a vile and abandoned life, and wrought the ruin of body and soul by licentiousness of every kind. Not content with this, they even overstepped the bounds which nature had defined, and together committed incredible and nameless crimes, “men with men (in the words of the sacred writer) working un-seemliness, and receiving in themselves that recompense of their error which was due.”
12. Nor did they stop even here; but perverted their natural thoughts of God, and denied that the course of this world was directed by his providential care, ascribing the existence and constitution of all things to the blind operation of chance, or the necessity of fate.
13. Once more: believing that soul and body were alike dissolved by death, they led a brutish life, unworthy of the name: careless of the nature or existence of the soul, they dreaded not the tribunal of Divine justice, expected no reward of virtue, nor thought of chastisement as the penalty of an evil life.
14. Hence it was that whole nations, a prey to wickedness in all its forms, were wasted by the effects of their own brutality: some living in the practice of most vile and lawless incest with mothers, others with sisters, and others again corrupting their own daughters. Some were found who slew their confiding guests; others who fed on human flesh; some strangled, and then feasted on, their aged men; others threw them alive to dogs. The time would fail me were I to attempt to describe the multifarious symptoms of the inveterate malady which had asserted its dominion over the whole human race.
15. Such, and numberless others like these, were the prevailing evils, on account of which the gracious Word of God, full of compassion for his human flock, had long since, by the ministry of his prophets, and earlier still, as well as later, by that of men distinguished by pious devotion to God, invited those thus desperately afflicted to their own cure; and had, by means of laws, exhortations, and doctrines of every kind, proclaimed to man the principles and elements of true godliness. But when for mankind, distracted and torn as I have said, not indeed by wolves and savage beasts, but by ruthless and soul-destroying spirits of evil, human power no longer sufficed, but a help was needed superior to that of man; then it was that the Word of God, obedient to his all-gracious Father's will, at length himself appeared, and most willingly made his abode among us.
16. The causes of his advent I have already described, induced by which he condescended to the society of man; not in his wonted form and manner, for he is incorporeal, and present everywhere throughout the world, proving by his agency both in heaven and earth the greatness of his almighty power, but in a character new and hitherto unknown. Assuming a mortal body, he deigned to associate and converse with men; desiring, through the medium of their own likeness, to save our mortal race.
Source: Oration in Praise of Constantine (New Advent)