The prophetic voice is the tragic voice
`The Christian preacher is not the successor of the Greek orator, but of the Hebrew prophet. The orator comes with but an inspiration, the prophet comes with a revelation. In so far as the preacher and prophet had an anaologue in Greece, it was the dramatist, with his urgent sense of life's guilty tragedy, its inevitable ethic, its unseen moral powers, and their atoning, purifying note. Moreover, where you have the passion for oratory you are not unlikely to have an impaired style and standard of preaching. Where your object is to secure your audience, rather than your Gospel, preaching is sure to suffer....[T]he only business of the apostolic preacher is to make men practically realize a world unseen and spiritual; he has to rouse them not against a common enemy but against their common selves; not against natural obstacles but against spiritual foes; and he has to call out not natural resources bu supernatural aids. Indeed, he has to tell men that their natural resources are so inadequate for the last purposes of life and its worst foes that they need from the supernatural much more than aid. They need deliverance, not a helper merely but a Saviour. The note of the preacher is the Gospel of a Saviour. The orator stirs men to rally, the preacher invites them to be redeemed. Demosthenes fires his audience to attack Philip straightway; Paul stirs them to die and rise with Christ. The orator, at most, may urge men to love their brother, the preacher beseeches them first to be reconciled to their Father. With preaching Christianity stands or falls because it is the declaration of a Gospel. Nay, more -- far more -- it is the Gospel prolonging and declaring itself.'
In other words, the orator is the one who has an impact through aesthetics, the great philosophical preoccupation of postmodernism and so much of the theology which takes its cue from this cultural predisposition; the preacher, by contrast, brings home the tragedy of the human condition and presents Christ crucified.