He who teaches will rather avoid all words that do not teach. If he can find correct words that are understood, he will choose those; if he cannot, whether because they do not exist or because they do not occur to him at the time, he will use even words that are less correct, provided only the thing itself be taught and learned correctly. ix. The correctness (_integritas_) of diction boasted by the sophists, and carried by them even to the pedantry of archaism, is here faced squarely. The assertion that it must sometimes be sacrificed, the making of clearness absolutely paramount, is the bolder at a time when Christian preaching was not yet recognized as having secure command of elegance. Unmistakable clearness, Augustine goes on, is so much more important in preaching than in discussions permitting question and answer that the speaker must be quick to help unspoken difficulties. For a crowd eager to grasp will show by its movement whether it has understood; and until it has given this signal the subject must be turned over and over by various ways of expressing it—a resource beyond the power of those who deliver speeches written out and memorized.[17] x. No warrant here, he adds (xi), for dilation beyond the demands of clearness, but good warrant for making instruction pleasant and appealing in order to hold attention. Passing thus to the two other tasks of oratory, he quotes (xii) Cicero’s “to instruct is of necessity, to please is for interest, to move is for victory.”[18] The three are then both carefully distinguished and shown to be a sort of geometrical progression. The first is first of necessity. It must be mastered; but it is rarely sufficient. To supply the lack, the second demands more rhetoric by demanding further adaptation to the audience; but it too must remain insufficient. So the third task, to move, is not merely the third item in a classification; it is the final stage in a progress. That progress is increasingly emotional. The last stage demands not only all the rhetoric of the preceding, but also the art of vivid imagery[19] and of urgent application. So Augustine arrives at one of those linking summaries which constitute almost a refrain. Therefore the eloquence of the Church, when it seeks to have something done, must not only explain to instruct and please to hold, but also move to win. xiii.