How Classical Rhetoric Became the Grammar of the Christian Sermon

Homiletics did not invent its own toolkit from nothing. When early Christian teachers needed a method for composing and delivering a sermon, they reached for the rhetorical training already given to any educated Roman, and the decisive translation of that training into a Christian task is a single book. Augustine of Hippo, himself a trained rhetorician before his conversion, wrote the fourth book of De Doctrina Christiana as a guide to Christian preaching built directly on Ciceronian rhetoric. He kept Cicero's three aims for a speaker, to teach, to delight and to persuade, and argued that a preacher owes a congregation all three: sound teaching stated clearly, language capable of holding attention, and a style forceful enough to move a hearer to act on what has been taught.

That inheritance shaped the sermon's basic architecture for over a thousand years afterward: an opening that secures the hearer's attention and goodwill, an exposition of the text or teaching at hand, and a closing application that asks something of the hearer's own life. Later homiletic traditions add and rearrange elements, and traditions outside Christianity developed preaching disciplines along different lines entirely, but the classical structure of teach, delight and persuade remains the reference point historians of preaching return to when describing what a sermon is doing and how it differs from a lecture or an essay read aloud.