Nowhere is the mystery of the three-in-one Godhead more clearly grasped than in St. Andrei Rublev's icon of the Trinity. Also known as the "Hospitality of Abraham," this icon is based on the Old Testament story in Genesis 18, where Abraham is visited by three young men (later identified as angels) presaging Trinitarian doctrine. It has become the image par excellence of the Holy Trinity for the Church.

In the icon the Biblical site of the oak grove at Mamre is indicated by a single tree, and Abraham's tent by the house in the upper left in this economical background. The total focus is on the three figures. Their role as angels is evidenced by their wings and by the thin staffs that they hold so lightly.

The composition is one that the eye discovers to be curvilinear as it is led from one angel to the other, following the tilts of the heads, the gazes of the eyes, and the fold of the robes. Even the tree leans in a gentle arc. But on closer observation, there is movement in the icon; it is energized.

The identity of Father, Son, and Holy Spirit from left to right is based on their order of mention in the creed of the faith. The role of Christ here is not based on His incarnation as the God-Man but as the Second Person of the Trinity equal in all ways: hence the identical faces and the absence of the cruciferous nimbus, Christ's traditional halo enclosing His cross and specific to Him in all other icons.

The colors of the garments are significant. The Father's mantle is yellowish-pink, somewhat diaphanous, and blends more than the others into the totality of the scene; indeed His role in the Creed resides in the first article alone, but undergirds the entire creed. The second person appears in Christ's traditional garb, which is the reddish purple chiton (tunic) with the golden clavus, the stripe of cloth on the right side which falls over the shoulder to the hem of the garment, which indicated noble rank in Roman times. It is surmounted by a blue mantle. The Holy Spirit angel wears the green of freshening and renewal, which He inspires. Green is the color of spring and rebirth in creation. It and blue are the most prevalent colors in nature. A variation of this blue appears in the mantle of the Christ angel.

Over and above composition and color is the aura of peace and tranquility that is evoked by this scene. A serene, soft joy permeates the faces and a calm exceeding ordinary stillness exudes from the relationship of the three angels. Therein lies the "perichoretic dance" of love in unity which is the essence of the Trinity - unity in and through love.