5 And as for the writings of the Greeks, they are all put out and vanished, but this man's shine brighter day by day. For from the time that he (was) and the other fishermen, since then the (doctrines) of Pythagoras and of Plato, which seemed before to prevail, have ceased to be spoken of, and most men do not know them even by name. Yet Plato was, they say, the invited companion of kings, had many friends, and sailed to Sicily. And Pythagoras occupied Magna Græcia, and practiced there ten thousand kinds of sorcery. For to converse with oxen, (which they say he did,) was nothing else but a piece of sorcery. As is most clear from this. He that so conversed with brutes did not in anything benefit the race of men, but even did them the greatest wrong. Yet surely, the nature of men was better adapted for the reasoning of philosophy; still he did, as they say, converse with eagles and oxen, using sorceries. For he did not make their irrational nature rational, (this was impossible to man,) but by his magic tricks he deceived the foolish. And neglecting to teach men anything useful, he taught that they might as well eat the heads of those who begot them, as beans. And he persuaded those who associated with him, that the soul of their teacher had actually been at one time a bush, at another a girl, at another a fish.
Are not these things with good cause extinct, and vanished utterly? With good cause, and reasonably. But not so the words of him who was ignorant and unlettered; for Syrians, and Egyptians, and Indians, and Persians, and Ethiopians, and ten thousand other nations, translating into their own tongues the doctrines introduced by him, barbarians though they be, have learned to philosophize. I did not therefore idly say that all the world has become his theater. For he did not leave those of his own kind, and waste his labor on the irrational creatures, (an act of excessive vainglory and extreme folly,) but being clear of this as well as of other passions, he was earnest on one point only, that all the world might learn somewhat of the things which might profit it, and be able to translate it from earth to heaven.
For this reason too, he did not hide his teaching in mist and darkness, as they did who threw obscurity of speech, like a kind of veil, around the mischiefs laid up within. But this man's doctrines are clearer than the sunbeams, wherefore they have been unfolded to all men throughout the world. For he did not teach as Pythagoras did, commanding those who came to him to be silent for five years, or to sit like senseless stones; neither did he invent fables defining the universe to consist of numbers; but casting away all this devilish trash and mischief, he diffused such simplicity through his words, that all he said was plain, not only to wise men, but also to women and youths. For he was persuaded that the words were true and profitable to all that should hearken to them. And all time after him is his witness; since he has drawn to him all the world, and has freed our life when we have listened to these words from all monstrous display of wisdom; wherefore we who hear them would prefer rather to give up our lives, than the doctrines by him delivered to us.
Source: Homilies on the Gospel of John (New Advent)