The historical significance of the _De doctrina christiana_, important as it is, should not obscure its value as a contribution to homiletic. The first homiletic, though one of the briefest, remains one of the most suggestive. It omits no essential; while it reminds us of the general principles of rhetoric, it emphasizes those applications to preaching which are distinctive; and it proceeds pedagogically. Though the _doctrina_ of the title refers strictly to exposition, and this is amplified and iterated as a constant necessity, Augustine includes specifically and from the start both charm and appeal, and concludes by showing emotional appeal to be the final stage of the comprehensive task of persuasion. Homiletic is an application of rhetoric long established as permanent, consistent, and in both materials and conditions fairly constant. That it is also comprehensive, demanding all three typical styles, including argument in its exposition, winning sympathy in order to urge action, varying its art[26] while holding to its single aim, is most suggestively established here in its first great monument. Not only does Augustine forbid the arid and the tedious, not only does he insist on emotional appeal; he also vindicates for Christian eloquence the importance of charm. This was the more delicate because charm was both abused by contemporary sophists and still suspected by contemporary preachers. Augustine presents it at once frankly and with just discrimination. To make it an end in itself, he is careful to show, is indeed sophistic; but to ignore it is to forget that preaching is a form of the oratory of occasion.[27] The Areopagus speech of St. Paul,[28] though it is only summarized in _Acts_ xvii, is evidently occasional, and has clear indications of that adaptation to win sympathy which is Augustine’s interpretation of Cicero’s _delectare_. The speech on occasion, favorite form of oratory in Augustine’s time, had been conventionalized to the point of recipe. The recipes, though he knew them all, Augustine simply ignores; the field he redeems. He shows Christian preaching how to cultivate it for real harvest. History has shown no other direction of rhetoric to be so peculiarly homiletic.