The viewer's full attention is drawn to the large centre panel in which a divine liturgy is performed around the Lamb of God Jesus Christ in a green landscape with a high horizon. an altar stands in the middle on a small green mound possibly representing Mount Zion. the Lamb stands erect on the altar - alive but bleeding from a wound. It's blood spurts out into a chalice. The allusion is clear - Christ's death and ressurection - his sacrifice for humanity - are commemorated on the altar during every Mass. the scene as a whole referst to the Last supper when Jesus described the wine as his blood which he was to shed for all humanity to earn the forgiveness of its sins.