Imagine a movie scene of the Gospel of John. The disciples are gathered around the table immediately after Jesus has washed their feet. Jesus knows his betrayer and lets him go and do what he needs to do. He hands bread to Judas, and then Judas leaves.
Imagine then the movie screen is split in two. On the one side, you see Judas scurrying down narrow flights of stairs and out into the streets, making his way quickly among the shadows until he finds the Chief Priests. He makes his deal.
One the other side of the screen is Jesus among his disciples. He knows that Judas is out there, right at this very moment betraying him. What does Jesus do? He gathers his disciples in a delicate, intimate scene, and talks about love--the Greatest Commandment, no less. While Judas is making his deal, Jesus--in full knowledge of this betrayal--at the very moment this betrayal is happening--Jesus opens like a flower.
While there is no mention of "turning the other cheek" in the Gospel of John, there can be no better example. In the face of violence, Jesus turns and shows his best side. He does not tighten up in anger, or slink away in fear, or keep a grudge, or make a list. He talks about the importance--the sheer necessity--of loving one another. Judas turned and struck him in the cheek, but Jesus responded--not with his hurt side--but as if we were never hurt. He turned and responded from his other side, his unhurt cheek--not from his pain or fear, but out of love.
Some argue that the Gospel of John is problematic in that Jesus only mentions the greatest commandment to his closest disciples. Many have wondered if he's talking only about love among disciples for disciples. The role of Judas in this scene, however--even when he is not present at the meal any longer--is critical to understanding Jesus' message. Even if John focuses on relationships among disciples, the ability of Jesus to remain in love and respect Judas, even as the latter falters, shows how a disciple can respond to the rest of the world. This message of love is for all people.