The Tripersonal God: Understanding and Interpreting the Trinity.

The Tripersonal God: Understanding and Interpreting the Trinity
Gerald O'Collins, S.J.
Paulist, $16.95, 234 pp.

Karl Rahner once famously observed that most Christians profess the Trinity in their recitation of the creed but live as monotheists. Over the past generation, there has been a reorientation in focus away from speculation on the Trinitarian relations within the Godhead toward an attempt to understand the Trinity in the actual economy of salvation. As a kind of summing up of those many scholarly reflections, Gerald O'Collins, a beloved veteran professor at Rome's Gregorian University, has published the heart of his lectures on Trinitarian theology, presented (among other places) at Notre Dame during regular summer visits. What results from that summation is a passionately felt and thoroughly readable work on the tripersonal God. I myself made much use of it in preparation for some talks on the Trinity for an RCIA class.

O'Collins structures his work around three major questions: What does Scripture tell us about the Trinity? (The word itself [trinitas] was coined in the late second century by the North African writer Tertullian.) What does the subsequent witness of the liturgy and theological tradition say about this subject? And, finally, how is one to live as if the revelation of God as Trinitarian is central to faith?

In any number of places in the New Testament there are triadic formulations linking God the Father/Christ/Spirit or Holy Spirit. The most famous, of course, are in the stories about the baptism of Jesus, and the mission mandate at the end of the Gospel of Matthew to baptize "in the name of the Father and of the Son and of the Holy Spirit." There are similar formulations in prayers found in Pauline letters, which have been adapted for use in our liturgy: "The grace of Our Lord Jesus Christ, the love of God, and the fellowship of the Holy Spirit be with all of you" (2 Cor 13:13). O'Collins studies these and many other texts in the New Testament. He also notes the strong and early influence of such language in the liturgy and the development of the creeds.

It is one thing to articulate the three names of Father, Son and Holy Spirit, but it is quite another to reflect on what they mean and how they can and cannot be understood. One of the burdens of early Christian writers (Justin Martyr in the second century is a prime example) was to show that such affirmations did not imply polytheism. O'Collins does a good job explaining how the debates of the fourth century finally ended with the affirmations of the councils running from Nicaea to Chalcedon. His historical discussion, covering just under eighty pages, is a model of clarity and concision.

In the final third of his work, O'Collins takes up contemporary thinking about the Trinity and the relationship of that thinking to actual Christian practice. He worries about some new forms of naming because of their tendency to modalism, but rightly points out that there is much to be gained by remembering that at the heart of the Christian understanding of God is the key fact that God is relational. That relationality allows us to speak to God through Christ by the power of the Holy Spirit.

Lawrence S. Cunningham is the John A. O'Brien Professor of Theology at the University of Notre Dame.