On Christian DoctrineAugustine

On Christian Doctrine is Augustine's manual for interpreting Scripture and communicating its meaning. The first three books develop a theory of signs and interpretation; the fourth applies classical rhetorical theory to Christian preaching. The work bridges the liberal arts tradition of Roman education and the new demands of a religion grounded in sacred texts.

Augustine distinguishes things and signs. Things are to be enjoyed (God) or used (everything else) according to their place in the order of love. Signs are things that point beyond themselves: words, sacraments, the events of Scripture. Biblical interpretation requires knowledge of languages, history, natural science, and the liberal arts, all subordinated to the rule of charity. If an interpretation does not build up the love of God and neighbor, it has gone wrong, regardless of its philological plausibility.

Book IV breaks decisively with the idea that Christian truth needs no rhetorical art. Augustine argues that since the opponents of truth use eloquence, its defenders cannot afford to neglect it. He draws on Cicero's three levels of style (plain, moderate, and grand) and illustrates each from Scripture and the Church Fathers. The result is a theory of Christian eloquence that values clarity above ornamentation but does not despise persuasion. On Christian Doctrine shaped medieval education, hermeneutics, and homiletics for a thousand years.