God is merciful. This is a biblical commonplace. But how God is merciful is a theological conundrum, especially if we conceive of God in metaphysical terms as pure being. Walter Kasper notes in this stimulating book that “God’s mercy has not found its place within this framework.” To ask how one of God’s primary attributes is mercy is to ask profound questions that go to the heart of Christian theology: How does God’s mercy comport with God’s justice? How does God’s mercy affect God’s salvific will? What is the relationship of God’s mercy to the trinitarian revelation of God in the Christian dispensation? Does the fact that God is merciful mean that God suffers, and if so, what about divine impassibility?

Kasper’s original intention was to compose a set of texts about God’s mercy for some retreat conferences. His motive at that time was purely pastoral, and his reflections were largely biblical.

Ex­cellent theologian that he is, however, he found himself meditating on God’s mercy in a far larger context because to think of God as merciful enlarges the way we think about God. Kasper’s contemplation of mercy evolved into a study that is deeply theological but still quite pastoral for at least one important reader, Pope Francis, who found it of enormous value in his own ministry.