A young man once asked Jesus, “What good must I do to have eternal life?” In reflecting on this line, St John Paul II said that this “is an essential and unavoidable question” that each person wonders about, and that we cannot help but sense “there is a connection between moral good and the fulfilment of [our] destiny… For the young man, the question is not so much about rules to be followed, but about the full meaning of life.” In this three-part series, we will explore the rich foundations of Catholic moral theology, taking St John Paul II as our guide.