Mark McIntosh ( Divine Teaching: An Introduction to Christian Theology (Blackwell Guides to Theology) ) points out that the most dramatic and clearest revelation of the Trinity in the gospel story occurs at the beginning, in Jesus’ baptism: “It is precisely as he unites himself with the people in their longing and need that Jesus is depicted as sensing fully his identity as God’s beloved.  It is then that the gospels describe him as being marked externally by an outpouring and anointing of God’s Spirit.” And this means that “the loving abundance that Jesus knows as the very root of his being . . . is the expression within our world of an eternal abundance.  It is the expression in our world of an infinite giving, the free self-sharing of the Father to the Son and in the Spirit, or what Christians call the Trinity.”

McIntosh’s book is full of neat twists.  Like this: In emphasizing the unity of God, Augustine and Aquinas are not trying “to confine trinitarian theology within some kind of philosophical preconception about divine essence,” but rather insisting on the continuity of Israel and the church: “they want to show that the God whom Christians adore as Father, Son, and Holy Spirit is non other than the one God of Israel, the Creator of heaven and earth.”  And this, summarizing Barth’s view of election and Trinity: “the trinitarian pattern of divine life is not simply a making space for the other, but an active and eternal choosing of the other.”

In addition to his own explorations of basic topics in theology, he includes fairly extended treatments of key historical figures and debates (“Landmarks”) and sketches out the contours of current debate (“Pathfinding”).  The whole book is premised on the notions that “Christian theology is an expression of an ongoing transformation of the world in encounter with God” and that to be done rightly, theology must be more than a “respectable discipline managed by theologians” and become “a mysterious sharing in God’s way of life, God’s talk . . . , God’s knowing and loving of Godself.”  And he assumes, somewhat radically orthodoxly, that “assimilating theology’s own mode of reflection to those of, say, cultural anthropology or philosophy or psychology, will only short-circuit theology’s unique aptness for getting at truth in certain ways that other disciplines do not.”