The Sacrifices of Abel and Melchizedech
Basilica of San Vitale, Ravenna
This mosaic is on the right side of the space that precedes the presbytery, where the clergy celebrate the Eucharistic liturgy, which is considered a memorializing re-enactment of the sacrifice of Christ on the Cross. Appropriately, both this and the mosaic on the left side focus on sacrifices in the Old Testament that prefigure the sacrifice of Christ on the Cross.
In the large lunette Abel offers a lamb and Melchizedech a loaf. The wine that Melchizedech also offered is already in a chalice on the altar. Like his garments, the structure behind Abel is simple and rustic, but in its shape and position it presages the church that stands behind Melchizedech, who is dressed as a priest. God's acceptance of the sacrifices is represented by the hand reaching down from the sky.
The sacrifice of Abel is in Genesis 4:1-8; that of Melchizedech, Genesis 14:18-20. Both sacrifices, of course, relate to the liturgy that is celebrated in this place. The bread and wine prefigures the elements of the Eucharist, and the lamb prefigures Christ himself.
On the right, Moses is feeding his sheep (lower register) when he comes upon the burning bush and is told to remove his sandals (upper register). His pallium and the scroll that he carries in his left hand mark him as a philosopher, just as the pallium and basket of scrolls do for Matthew in the upper left of the composition. The scroll has the additional function of signifying Moses' commission to lead the Israelites to freedom. This is pictured in the corresponding segment on the right side of the facing wall.
On the left Isaiah stands outside a city holding a scroll that is commonly his attribute. Together he and Moses represent "the Law and the Prophets," that is, the Old Testament, while the two evangelists above represent the New.
Between the Moses and Isaiah panels, angels hold a clipeus with a jeweled cross representing Christ, whose sacrifice is prefigured by those of Abel and Melchizedech and in whom "the Law and the Prophets" are fulfilled, according to Luke 24:44 and John 1:45. See a detailed explanation of the identical panel on the facing wall.
The portraits of the evangelists Matthew and Mark in the uppermost register correspond to John and Luke's portraits on the facing wall.
This image in full resolution
View the mosaic on the left side facing this one
Photographed at the basilica by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.