Bay 3 - The 'New Alliance'
Panel 12 - King David / Pelican feeding its young
Christ's descent from King David was a commonplace both in the depictions of the Tree of Jesse and in the Biblical texts. The plea "Son of David have pity upon me/us" or minor variants thereof occur frequently in the Gospels (e.g. Matthew 15:22, 20:30, 20:31, Mark 10:47, 10:48, Luke 18:39, etc.)
The pelican pecking at its chest was a common symbol of Christ (often
shown at the top of a crucifix) due to the popular belief that the bird
fed it's young on its own blood. It therefore referred to the nourishing/salvific
function of the Eucharist.