Trinity Sunday gives us a wonderful moment to reflect on how mysterious God is, how little we can say no matter how vast our desire. It also prompts us to recall that cardinal Bible sin, idolatry: false claims about God, often overbalanced toward certainty and projection, i.e., making God too much like ourselves. John’s Gospel is the best place to find good language about the Trinity, while the Old Testament offers less, with today’s passage from Proverbs suggesting a partner for God, albeit a creaturely one. What I find more helpful is Karen Armstrong’s description of how the Eastern medieval tradition read Genesis 18. Let me offer that passage for reflection:
One of the most famous icons of all times is The Old Testament Trinity by the fifteenth-century Russian painter Alexander Rublev...based on the story of Abraham and the three strangers, whom Rublev depicts as angels, messengers of the unknowable God. Each represents one of the Trinitarian “persons”; they look interchangeable and can be identified only by their symbolically colored garments and the emblem behind each one. Abraham’s table has become an altar, and the elaborate meal he prepared has been reduced to the Eucharistic cup. The three angels sit in a circle, emblem of perfection and infinity, and the viewer is positioned on the empty side of the table. Immediately Rublev suggests that Christians can experience the truth of the Trinity in the Eucharistic liturgy, in communion with God and one another, and—recalling the Genesis story—in a life of compassion. The central angel representing the Son immediately attracts our attention, yet he does not return our gaze but looks toward the Father, the angel on his right. Instead of returning his regard, the Father directs his attention to the figure at the right of the painting, whose gaze is directed within. We are thus drawn into the perpetual circling motion described by Gregory of Nazianzus. This is not an overbearing deity, demanding exclusive loyalty and total attention to himself. We meet not of the prosopoi [persons] head-on; each refers us to the other in eternal personal dispossession. There is no selfhood in the Trinity. Instead there is silence and kenosis [emptying of self].” (Karen Armstrong, The Case for God , pgs. 117-18).
Barbara Green, O.P.