A sermon is a religious discourse or oration by a preacher, usually a member of clergy. Sermons address a scriptural, theological, or moral topic, usually expounding on a type of belief, law, or behavior within both past and present contexts. Elements of the sermon often include exposition, exhortation, and practical application. The act of delivering a sermon is called preaching. In secular usage, the word sermon may refer, often disparagingly, to a lecture on morals.