Chapter 13 is the beginning of the second part of the Gospel of John, sometimes called the Book of Glory. Its central theme is how Jesus is glorified through his Passion, death, and Resurrection. It begins with Jesus’ washing the disciples’ feet at the Last Supper, before the Passover.
The Jewish feast of Passover, also called the feast of Unleavened Bread, reminds us how God rescued the Israelites from slavery in Egypt by killing the firstborn Egyptians and ‘passing over’ the homes of the Israelites (about 1250 B.C.) The feast was traditionally celebrated with a meal of lamb, bitter herbs, and unleavened bread (Exodus 12:14-28). It was blood of a lamb, smeared on the doorposts of the Israelites’ houses, that signaled the angel of death to spare the first-born of God’s people.
In other Gospels, the last meal that Jesus shares with his disciples is the Passover meal. However, in the Gospel of John, Jesus is arrested before Passover. He is crucified on the preparation day of the feast of Unleavened Bread, at the same time that the lambs are being sacrificed in the Temple. The symbolism cannot be missed by the readers of John: Jesus is the new and perfect Passover Lamb.