In a world marked by division, indifference, and suffering, mercy can seem like a fragile or even outdated ideal. Yet in this profound and timely work, Cardinal Walter Kasper argues that mercy is not only relevant—it is essential. Indeed, it is the very heart of the Gospel and the key to understanding Christian life today.

Building on his landmark study Mercy: The Essence of the Gospel and the Key to Christian Life—a work that Pope Francis praised, saying, "This book has done me so much good"—Kasper here offers a clear, accessible presentation of his central insight: that mercy is the defining attribute of God and the foundation of authentic human existence.

Drawing deeply from Scripture, theology, and the lived experience of the Church, The Challenge of Mercy traces the biblical vision of a God who hears the cry of his people and, in Jesus Christ, reveals mercy as the fullness of divine love. Mercy is not opposed to justice, Kasper shows, but fulfills it.

At once intellectually rigorous and pastorally compelling, this book offers a vision of Christianity that is both faithful to tradition and responsive to the needs of our time. It is an invitation to encounter the God who is rich in mercy—and to become, in turn, agents of that mercy in a wounded world.

Walter Kasper is a German cardinal of the Roman Catholic Church. He is president emeritus of the Pontifical Council for Promoting Christian Unity. He is the author of Accepting the Mystery: Scriptural Reflections for Advent and Christmas and A Path into Life: Reflections for Lent and Easter.