13 You are, no doubt, men of vast acquirements; but we too have studied in the schools, and, like you, we have learned from the precepts of Aristotle— or, rather, from those which he has derived from Gorgias— that there are different ways of speaking; and we know, among other things, that he who writes for display uses one style, and he who writes to convince, another. In the former case the debate is desultory; to confute the opposer, now this argument is adduced and now that.
One argues as one pleases, saying one thing while one means another. To quote the proverb, “With one hand one offers bread, in the other one holds a stone.” In the latter case a certain frankness and openness of countenance are necessary. For it is one thing to start a problem and another to expound what is already proved. The first calls for a disputant, the second for a teacher. I stand in the thick of the fray, my life in constant danger: you who profess to teach me are a man of books.
“Do not,” you say, “attack unexpectedly or wound by a side-thrust. Strike straight at your opponent. You should be ashamed to resort to feints instead of force.” As if it were not the perfection of fighting to menace one part and to strike another. Read, I beg of you, Demosthenes or Cicero, or (if you do not care for pleaders whose aim is to speak plausibly rather than truly) read Plato, Theophrastus, Xenophon, Aristotle, and the rest of those who draw their respective rills of wisdom from the Socratic fountain-head.
Do they show any openness? Are they devoid of artifice? Is not every word they say filled with meaning? And does not this meaning always make for victory? Origen, Methodius, Eusebius, and Apollinaris write at great length against Celsus and Porphyry. Consider how subtle are the arguments, how insidious the engines with which they overthrow what the spirit of the devil has wrought. Sometimes, it is true, they are compelled to say not what they think but what is needful; and for this reason they employ against their opponents the assertions of the Gentiles themselves.
I say nothing of the Latin authors, of Tertullian, Cyprian, Minutius, Victorinus, Lactantius, Hilary, lest I should appear not so much to be defending myself as to be assailing others. I will only mention the Apostle Paul, whose words seem to me, as often as I hear them, to be not words, but peals of thunder. Read his epistles, and especially those addressed to the Romans, to the Galatians, and to the Ephesians, in all of which he stands in the thick of the battle, and you will see how skilful and how careful he is in the proofs which he draws from the Old Testament, and how warily he cloaks the object which he has in view.
His words seem simplicity itself: the expressions of a guileless and unsophisticated person— one who has no skill either to plan a dilemma or to avoid it. Still, whichever way you look, they are thunderbolts. His pleading halts, yet he carries every point which he takes up. He turns his back upon his foe only to overcome him; he simulates flight, but only that he may slay. He, then, if any one, ought to be calumniated; we should speak thus to him: “The proofs which you have used against the Jews or against other heretics bear a different meaning in their own contexts to that which they bear in your epistles.
We see passages taken captive by your pen and pressed into service to win you a victory which in the volumes from which they are taken have no controversial bearing at all.” May he not reply to us in the words of the Saviour: “I have one mode of speech for those that are without and another for those that are within; the crowds hear my parables, but their interpretation is for my disciples alone”? The Lord puts questions to the Pharisees, but does not elucidate them. To teach a disciple is one thing; to vanquish an opponent, another. “My mystery is for me,” says the prophet; “my mystery is for me and for them that are mine.”
Source: Letters (New Advent)