Leonardo's The Last Supper depicts the sequence of events before Jesus's betrayal and crucifixion. Rather than merely a snapshot in time, The Last Supper seems to be a continuous sequence of events, and a foreshadow of events to come. Two interpretations of the subject of the painting come to mind: the betrayal announcement and the first communion. Observing the impulsive Simon Peter's interactions with Judas and John, Jesus and Thomas, it is clear that The Last Supper represents a conjoint presence of both the betrayal announcement and the institution of the Eucharist.
The main theme behind The Last Supper is Jesus's death. Jesus came to earth to be crucified as the sacrifice for the sins of mankind. Man cannot become righteous by his own works and are thus condemned to hell. But Jesus comes as a sacrifice to pay for those sins and thus all who trust in him and give their lives to God will be forgiven of their sins. This is what the Eucharist represents. The bread is Jesus's body broken for man, and it symbolizes Jesus's sacrifice on the cross. From a secular viewpoint, the Eucharist means nothing, so the main theme is obviously Jesus's announcement of the betrayal. Jesus already knows that Judas will betray him and accepts it because the betrayal is but one part of God's plan. The reactions of the apostles as seen in the painting seem to differ, as some react to the betrayal while others appear to be receiving communion.
Peter's placement on the left side of the painting and his placement between John and Judas reflects his character. The painting is divided with six apostles on either side of Jesus. The ones on the right are beside a lighted wall, whereas the ones on the left sink into the shadows. Peter is on the darkened side, which contains (from left) Bartholomew, James the Lesser, Andrew, Judas, Peter and John. This dark side is considered to be the "death side" of the painting. At first glance, their reactions seem to react to the immediate announcement of the betrayer. But as we look deeper, their gestures also foreshadow events to come. Steinberg comments that left side of Christ were "his slower-witted disciples" responding to the announcement of the betrayal while those on his right were responding to his initiation of the Eucharist (p. 38). John, Judas and Peter form a triad on the left. Being the worldly impulsive person he is, he would have immediately reacted to the announcement of the betrayal instead of the deeper institution of the Eucharist.
The reactions of the triad are in complete contrast, with the impulsive Peter, the traitorous Judas and the passive John. John's hands are folded and reserved, while his head is leaned in towards Peter. There are not enough plates and cups for everyone in the picture, so Jesus borrows John's set. "Better to notice that John's `personal' glass and platter approach our side of the table while his hands withdraw and recede. These hands advance no possessive claims; they disown."...