It's now just before Passover, and Jesus knows he's got to die this weekend. First, god lets the devil enter Judas Iscariot's heart. Then, Jesus takes off his robe and wraps a towel around his waist. He washes the disciples' feet and dries them with same. Simon Peter gets a little squicky at the erotic overtones of another man washing his feet and tries to refuse. Jesus informs him that he doesn't get it and if he doesn't accept this foot bath, he can't go to heaven. Peter takes a deep breath and asks him to wash everything, then. Jesus, who, mind, used to tell us it isn't necessary to wash our hands before eating, stays true to form and says if you've had a bath recently you only need to clean your feet in between. He informs the disciples that most of them are clean enough, but not all, meaning Judas. Then he puts his clothes back on and tells them to wash each others' feet from now on.
Now he starts to talk about his own death, a subject he never, ever gets tired of. He explains that one of them is going to betray him. Of course they want to know who, and he draws it out as long and dramatically as possible, dipping a piece of bread in the gravy and saying the person he passes it to will be the one to betray him, then handing it to Judas, rather than just saying 'Judas will do the deed.' Judas eats the bread, which allows Satan to enter into his body, again. Jesus asks him to get it over with quickly.
Even now that Jesus has explained what is going to happen, the disciples still don't get it. Some of them think Jesus is instructing Judas to buy provisions for the feast, others think he's telling him to give alms to the poor. Regardless, Judas leaves right away.
As soon as he's gone, Jesus tells the others he has a new commandment for them: That ye love one another; as I have loved you, that ye
also love one another. (v. 34) He says he has to go away soon, and they can't come after him yet. Peter gets a bit whiny, asking why he can't go now, and swearing he would lay down his life for him. Jesus mocks him and says he'll deny him three times that night.