Scala/Art Resource, New York, NY

In a lunette on the opposite side of the sanctuary lies a similar mosaic (compare with previous photo) that depicts Abel, left, offering a lamb and the priest Melchizedek (see Genesis 14:18), right, offering bread to God. God’s hand points down to a chalice of wine and two patens with bread on an altar. The placement of the lunettes and their similar design and content draw these stories together: The scene with Melchizedek foreshadows Jesus’ death on the cross, represented by the sacrament of the Eucharist, and Isaac’s near-sacrifice also prefigures this ultimate sacrifice.