The left window pane depicts Moses under a symbol of the triune God and the tablets of the Law received by Moses are below his image.
The right pane depicts David and below the Loaves of Proposition, also known as the “Bread of the Presence” or “Showbread”. The “loaves of proposition” were twelve loaves of bread, representing the twelve tribes of Israel, placed on a table of pure gold in the Tabernacle. They were a “continual” offering signifying God’s presence and covenant with the people. Every Sabbath, the Levis or priests were to replace the old, “stale” loaves with fresh, hot ones. The old loaves, having been in the presence of Yahweh for a week, were considered “most holy”. They belonged exclusively to those Levis serving the Temple, who were required to eat them within a “holy place” (the courtyard of the Tabernacle).
David and symbols related to him are above the loaves (e.g. harp) and references the story in 1 Samuel 21:1–6 where David is running from King Saul, who has tried to kill him. He leaves in a hurry, with no food or weapons. David comes to Nob, where the tabernacle was kept at the time, and meets Ahimelech the priest. Ahimelech is alarmed to see him alone. David says he is on a secret mission for the king and that his young men are waiting nearby. He asks for five loaves or whatever food there is. The priest has no ordinary bread, only the holy bread. Ahimelech agrees to give it on one condition: the men must be ritually clean, meaning they have kept away from women. David assures him they have, as they always do on a mission. So the priest gives David the bread that had just been taken from before the Lord. David also takes Goliath’s sword (see this below the loaves), which is kept there.
Jesus brings up this story of David when the Pharisees criticize his disciples for picking grain on the Sabbath (Matthew 12:1–8, Mark 2:23–28, Luke 6:1–5). His point is that human need can take priority over ritual rules. Also, tradition has long seen the holy loaves as a foreshadowing of the Eucharist – the Blessed Sacrament. The bread once kept in God’s presence for priests alone is now offered in Christ, the Son of David, as his own Body. He gives it to all his hungry followers, and in it we receive the Presence itself, the Bread of Life come down from heaven (John 6:51)