The icon depicts the three angels who visited Abraham at the Oak of Mamre (Genesis 18:1–8), but the painting is full of symbolism and is interpreted as an icon of the Holy Trinity. The left angel symbolizes God the Father. He blesses the cup, yet his hand is painted in a distance, as if he passes the cup to the central angel. Viktor Lazarev suggests that the central angel represents Jesus Christ, who in turn blesses the cup as well and accepts it with a bow as if saying "My Father, if it is possible, may this cup be taken from me. Yet not as I will, but as you will" (Mt 26:39). The starting point of the Trinity is the Father, therefore Rublev places Abraham's house above the corresponding angel's head. The Oak of Mamre can be interpreted as the tree of life, and it serves as a reminder of the Jesus's death on the cross and his subsequent resurrection, which opened the way to eternal life. The Oak is located in the centre, above the angel who symbolizes Jesus. Finally, the mountain is a symbol of the spiritual ascent, which mankind accomplishes with the help of the Holy Spirit. The wings of two angels, the Father and the Son, interlap. The blue colour of the Son's robe symbolizes divinity, the brown colour represents earth, his humanity, and the gold speaks of kingship of God. The wings of the Holy Spirit do not touch the Son's wings, they are imperceptibly divided by the Son's spear. The blue colour of the Holy Spirit's robe symbolizes divinity, the green colour represents new life. The poses and the inclinations of the Holy Spirit and the Son's heads demonstrate their submission to the Father, yet their placement on the thrones at the same level symbolizes equality.
Angels at Mamre (Holy Trinity) by Andrei Rublev available at under a Public Domain licence.