The moral language and operating norms of business find their roots in Judaism, Catholicism and Protestantism. Judaism gives business ethics a set of operative norms, upon which Christianity builds to identify principles, that reflect the complexity and diversity of business activity outside the ancient Jewish world. Early Christian traditions influenced heavily by the work of St. Ambrose, Augustine, and Thomas, plus the contemporary contributions of Catholic social thought articulated by Popes Leo XIII, John Paul II, Benedict XVI, and others, contribute to concepts of justice, virtue and specific acts in business and management. Luther, Weber, and others writing in the wake of the Protestant Reformation introduce in the language and norms of business ethics concepts like the vocation or “calling” to business as a type of ministry, the work ethic, and the spirit of economic activity.