2 This fisherman then, whose business was about lakes, and nets, and fish; this native of Bethsaida of Galilee; this son of a poor fisherman, yes, and poor to the last degree; this man ignorant, and to the last degree of ignorance too, who never learned letters either before or after he accompanied Christ; let us see what he utters, and on what matters he converses with us. Is it of things in the field? Is it of things in rivers? On the trade in fish? For these things, perhaps, one expects to hear from a fisherman.
But fear not; we shall hear nought of these; but we shall hear of things in heaven, and what no one ever learned before this man. For, as might be expected of one who speaks from the very treasures of the Spirit, he has come bringing to us sublime doctrines, and the best way of life and wisdom, [as though just arrived from the very heavens; yea, rather such as it was not likely that all even there should know, as I said before.] Do these things belong to a fisherman? Tell me. Do they belong to a rhetorician at all?
To a sophist or philosopher? To every one trained in the wisdom of the Gentiles? By no means. The human soul is simply unable thus to philosophize on that pure and blessed nature; on the powers that come next to it; on immortality and endless life; on the nature of mortal bodies which shall hereafter be immortal; on punishment and the judgment to come; on the enquiries that shall be as to deeds and words, as to thoughts and imaginations. It cannot tell what is man, what the world; what is man indeed, and what he who seems to be man, but is not; what is the nature of virtue, what of vice.
Source: Homilies on the Gospel of John (New Advent)