Don't miss the Commonweal interview with Cardinal Walter Kasper  where he discusses his book Mercy: The Essence of the Gospel and the Key to Christian Life.
Here is a sample:
The God of the Old Testament is not an angry God but a merciful God, if you read the Psalms. This ontological understanding of God [as absolute being] was so strong that justice became the main attribute of God, not mercy. Thomas Aquinas clearly said that mercy is much more fundamental because God does not answer to the demands of our rules. Mercy is the faithfulness of God to his own being as love. Because God is love. And mercy is the love revealed to us in concrete deeds and words. So mercy becomes not only the central attribute of God, but also the key of Christian existence. Be merciful as God is merciful. We have to imitate God’s mercy.