Judas Iscariot
Judas Iscariot (died AD) was a disciple and one of the original Twelve Disciples of Jesus Christ. According to all four canonical gospels, Judas betrayed Jesus to the Sanhedrin in the Garden of Gethsemane by kissing him and addressing him as "Rabbi" to reveal his identity to the crowd who had come to arrest him. His name is often used synonymously with betrayal or treason. Judas's epithet "Iscariot" most likely means he came from the village of Kerioth, but this explanation is not universally accepted and many other possibilities have been suggested.
Giovanni Canavesio
This classical motif chosen by Canavesio was when Christ announces his coming betrayal and indirectly hints on Judas as the traitor. Both Christ and Judas reach their arms toward the tray in the center while Christ holds a piece of food. The traitor is revealed as well in the illustrations of Matthew (26:23)—Judas dipping his hand in the dish—and John (13:26)—Judas receiving the soup. The interaction of Christ and Judas is signified by Christ extending his right hand and Judas his left. That Peter holding a knife can frequently be interpreted as his combative mood that is often presented in theatrical episode, Canavesio has no intention of showing this motif but is influenced by Savoyard Passion Cycle.