27. Accordingly a great orator has truly said that “an eloquent man must speak so as to teach, to delight, and to persuade.” 1951 Then he adds: “To teach is a necessity, to delight is a beauty, to persuade is a triumph.” 1952 Now of these three, the one first mentioned, the teaching, which is a matter of necessity, depends on what we say; the other two on the way we say it. He, then, who speaks with the purpose of teaching should not suppose that he has said what he has to say as long as he is not understood; for although what he has said be intelligible to himself it is not said at all to the man who does not understand it. If, however, he is understood, he has said his say, whatever may have been his manner of saying it. But if he wishes to delight or persuade his hearer as well, he will not accomplish that end by putting his thought in any shape no matter what, but for that purpose the style of speaking is a matter of importance. And as the hearer must be pleased in order to secure his attention, so he must be persuaded in order to move him to action. And as he is pleased if you speak with sweetness and elegance, so he is persuaded if he be drawn by your promises, and awed by your threats; if he reject what you condemn, and embrace what you commend; if he grieve when you heap up objects for grief, and rejoice when you point out an object for joy; if he pity those whom you present to him as objects of pity, and shrink from those whom you set before him as men to be feared and shunned. I need not go over all the other things that can be done by powerful eloquence to move the minds of the hearers, not telling them what they ought to do, but urging them to do what they already know ought to be done.
28. If, however, they do not yet know this, they must of course be instructed before they can be moved. And perhaps the mere knowledge of their duty will have such an effect that there will be no need to move them with greater strength of eloquence. Yet when this is needful, it ought to be done. And it is needful when people, knowing what they ought to do, do it not. Therefore, to teach is a necessity. For what men know, it is in their own hands either to do or not to do. But who would say that it is their duty to do what they do not know? On the same principle, to persuade is not a necessity: for it is not always called for; as, for example, when the hearer yields his assent to one who simply teaches or gives pleasure. For this reason also to persuade is a triumph, because it is possible that a man may be taught and delighted, and yet not give his consent. And what will be the use of gaining the first two ends if we fail in the third? Neither is it a necessity to give pleasure; for when, in the course of an address, the truth is clearly pointed out (and this is the true function of teaching), it is not the fact, nor is it the intention, that the style of speech should make the truth pleasing, or that the style should of itself give pleasure; but the truth itself, when exhibited in its naked simplicity, gives pleasure, because it is the truth. And hence even falsities are frequently a source of pleasure when they are brought to light and exposed. It is not, of course, their falsity that gives pleasure; but as it is true that they are false, the speech which shows this to be true gives pleasure.