The Pharisee and the Publican
Church of Sant'Apollinare Nuovo, left side of nave
This is one of the 13 mosaics along the upper band of the left wall of the nave that follow the life of Christ. Deliyannis (154) identifies it as the parable of the Pharisee and the Publican: In the Temple, the Pharisee brags to God about his piety, while the publican prays "O God be merciful to me a sinner." Jesus says only the publican will go home "justified" because "every one that exalteth himself, shall be humbled: and he that humbleth himself, shall be exalted (Luke 18:9-14)."
In the mosaic, one might guess that the man on the left is the publican, bending his head and striking his breast as if in supplication, while the man on the right would be the Pharisee, standing upright in orant position.
But if this is so, it is not clear why the publican, or someone just like him with the same clothes, beard, and hair, appears again, apparently as an associate of Caiaphas, in the panels on Jesus' trial before the Sanhedrin and the Way of the Cross. Possibly the man on the right is really the publican, posed orant because truly praying, while the other gestures to him saying, "O God I give thee thanks that I am not as the rest of men, extortioners, unjust, adulterers, as also is this publican."
This is the only scene in the entire series from the life of Christ that does not have Jesus in it.
See also a view of the entire left wall with commentary on the iconography of Jesus and the apostles in these mosaics.
This image in full resolution
More of the Public Life of Jesus
Photographed at the church by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.