Christians regularly ask God to "forgive us our debts, as we forgive our debtors," but tend to focus on the first half and ignore the second. Something is missing if Christians think of mission only in terms of proclamation or social justice and discipleship only in terms of personal growth and renewal--leaving the relational implications of the gospel almost to chance. It is vital both to spiritual life and mission to think of the church as both invitation and witness to a particularly merciful social dynamic in the world. As a work of constructive practical theology and a critical...