Why would a Corinthian marry incestuously? Why would other Corinthian Christians boast of such a relationship? Why did Paul resort to excommunication in this case? This study of 1 Cor 5 offers well-argued, innovative answers to these questions, departing from traditional responses which presuppose a situation of polemic in which the Corinthians are contesting Paul's apostolic authority. In these pages, the author presents a fresh reading of Corinthian motives against a background of Stoic ideas and, through a careful rhetorical analysis of the dynamics of Paul's argument, locates its exigent character in Paul's concern for the sanctified life of the community.