
This is one of my favorite paintings, partly because I relate so much to Peter, who's always getting everything wrong. Like, he's the disciple who cuts off the soldier's ear when the Romans come to arrest Jesus (not that many hours after this foot washing).
You can just hear Jesus sigh, are they ever going to get this?
Talk about not getting the response you were hoping for.
Here Peter is looking all grumpy because he doesn't think it's proper that Jesus should take the role of a slave or lowly servant, foot washing being, of course, a demeaning task. But when Jesus explains it is necessary, then Peter gets all overenthusiastic and says Jesus should wash more of him too.
Peter is an idiot, and I am right there with him.