The art of sermon preparation employing exegesis, hermeneutics, and homiletics. The capacity to expound and explain scripture for exhortation and edification. The combined study of scriptural interpretation, textual application, and sermon delivery.
It has been around, in one form or another, since the time of the Romans and Ancient Greeks, who developed the rules and forms of rhetoric. By the Middle Ages, Catholic preachers made it their own. Geoffrey Chaucer outlines the main features of an outstanding sermon in the Pardoner's Tale of the Canterbury Tales.
By Shakespeare's time, rhetoric was part of the usual school curriculum and helped to shape the English reformation. In the seventeenth century, it also helped in the huge surge of nonconformist activity.
More recently, it has been adopted by political speechwriters who appreciate the power of preachology.
Preaching would be classified as a social science. The effects of preaching can be measured. A study was once conducted within a church congregation on the effects of preaching, testing participants in five categories: knowledge, pseudo-behavior, an evaluation on the participant's act of worship, an evaluation of the preacher, and a semantic differential.