No, said Peter, you shall never wash my feet. Jesus answered, Unless I wash you, you have no part with me
Peter's refusing to be washed by Jesus serves as a remarkable picture of the human need for the cleansing Jesus offers and the sinful pride of those who reject Jesus' cleansing ministry. Peter's actions ostensibly were prompted by humility. You can see the incredulity on his face when Jesus approaches him and he protests, Lord, You'll never do this to me! It sounds as though this is a humble statement, and that Peter is appalled that Jesus should ever take such a low position as to wash his feet.
At first glance it does appear as though Peter's expostulation arises out of his own sense of unworthiness before Jesus. But when you look a bit closer, you can see that it is really the expression of intense personal pride. Peter is offended by Jesus' actions because he knows that if he were a teacher, he would never consider stooping to wash someone's feet because it would be beneath him. This is a rebuke to his self-sufficiency. He doesn't want Jesus to wash his feet. He would be content to wash Jesus' feet, but it is an affront to his sense of independence that Jesus should do anything for him. Peter shows this same pride later on when he offers to lay down his life for Jesus; he doesn't want Jesus to lay down His life for him.
This is a revelation of the sinful pride of our own hearts, which often cloaks itself with a guise of humility, when we are really insisting on our self-sufficiency. We do not want to admit to anybody that we need anything. That is what Peter is doing here. He doesn't want to acknowledge his need to be washed, and, especially, of letting Jesus do this menial act for him. It humiliates him. And so he stands as an example of the pride in our own hearts that resists Jesus' ministry to us.
One of the remarkable things about the gospel is that it is always bringing us down to the lowest point. We must stand in utter humiliation in order for God to minister to us. All human pride must be brought low before Him before we can receive what God wants to give us from His hand. And that is where we struggle. We don't like to be delivered to a place where we have nothing to offer. We want to add something. Peter is a clear picture of this. Then when Jesus explains to him, Unless I wash you, you have no part with me, Peter immediately capitulates to the other extreme: Lord, if that's the case, then by all means--not my feet only but also my hands and my head! In other words, he asked for a bath.