As I've taught theology and fielded this question, two others follow closely: What use is the doctrine of the Trinity? And, Is it still relevant?
Stephen R. Holmes and Thomas H. McCall answer these questions in their essays on the doctrine of the Trinity appearing in the soon-to-be released book Two Views of the Doctrine of the Trinity. (Releasing 9/2/2014)
As a classical trinitarian, Holmes says ”If the doctrine has any use, it is in clarifying errors about its own articulation."
Representing relational trinitarianism, McCall argues it is relevant because “God created us to share in the divine life of holy love, and he has redeemed us so that we might be rescued from our sin and come home to that life.”
Read their excerpts to be reminded why the doctrine of the Trinity is still useful and relevant today.
-Jeremy Bouma, Th.M. (@bouma)