A relational ontology* focuses on personhood, relationship, and communion as the modality of all existence. This secures for Christian theology a basis for a theology of God that is inherently related to every facet of Christian life. To say that the doctrine of the Trinity is ultimately a practical doctrine with radical implications for Christian life makes sense when the theology of God is removed from the realm of speculation on God in se** to the real of reflection on God-for-us as revealed in creation, in the face of Jesus Christ, and in the power of the Holy Spirit who brings about communion between God and creature.
* ontology: the study or concept or understanding of being.
** in se: Latin for "in itself" [herself/himself/godself].
If you ponder this passage, you'll see that it is not as dense as it seems at first.
With thanks to FranIAm for drawing my attention to this quote from Catherine Mowry LaCugna's God For Us: The Trinity and Christian Life. (New York: HarperCollins, 1991, [pbk] 1993), 250.
That conversation took place today. Two days ago, on Saturday afternoon, I wrote this Facebook update:
Three friends from East, South, and West strolled on a yacht club boardwalk talking about the mysteries of the Holy Trinity. Srsly. Now we are writing. (Two theological works, one novel.) Tonight: silliness, boogie-ing, pre-nuptial and natal day (the groom's) festivities.
Who knew? Unlike Paul the BB, I am not among the 0.5 percent of preachers who like to preach on Trinity Sunday. Maybe this will change! I did once write a little something on the Trinity, to my own surprise.
I'll be on the road on Trinity Sunday, two weekends from now, so this is a little advance resource -- though there is never an inappropriate time to ponder the mysteries of the Trinity. (Another thing I thought I'd never say.)
Speaking of FranIAm, if you are a liturgical Christian (or perhaps even if you are not), you will like her "Ascension to Pentecost" series.
Or you can just ponder the Rublev icon.