Sister Faustina Kowalska, the Polish nun who had mystical encounters with the merciful Christ in the early 20th century, was canonized a saint by Pope John Paul II. The Pope also declared the first Sunday after Easter to be Divine Mercy Sunday, and it was during the vigil Mass of this feast that the Holy Father received his last Holy Communion and drew his last breath.

The message of Divine Mercy as communicated through Sister Faustina is both a starting point and a recurring theme for Cardinal Schönborn's discussion of God's merciful love. The Archbishop of Vienna explores the presence of God's great mercy in the Scriptures, Tradition, the life of Christ, and the sacraments and works of the Church, while raising important questions along the way, such as, "What is the relationship between mercy and justice?"

"Mercy is the central nucleus of the Gospel message. In our time humanity needs a strong proclamation and witness of God's mercy . . . Go forth and be witnesses of God's mercy, a source of hope for every person and for the whole world."
- Pope Benedict XVI