In John 13, when Jesus comes to Peter to wash his feet, Peter protests. “Whoa! This is all wrong! You’re the Messiah, what the heck are you doing down there with water and a towel washing my feet. That’s what the servant in the house is for. Maybe I should wash yours, but you are not washing mine.” Jesus then tells him that he must let him wash his feet. “If I don’t wash you, you have no share with me.” In other words, Jesus is telling Peter that he must be washed by Jesus or he has no real fellowship with Jesus, no part in what is being accomplished in Jesus, no share in the kingdom that belongs to Jesus. Peter then swings around completely and shows his enthusiasm for Jesus by saying, “Well then don’t stop with my feet. Wash my head, my hands, and whatever else you want to wash.” Then Jesus gives something of a double-edged retort to Peter. On the one hand he seems to say, “Cut the theatrics Peter. What I am doing here is a picture of my love for you, but it also points to something far more significant. If you can’t bring yourself to let me serve you by washing your feet, you won’t be able to enter in and receive what I am going to do for you tomorrow. You must let me serve you and cleanse you. You have no idea what will be required for your cleansing, but tomorrow you will begin to understand.” It wasn’t the footwashing that was the required washing to have a share in Jesus. It was what the footwashing pointed to – which was the greater act of service, the greater humility, the greater scandal of the Suffering Servant of God, the Messiah, Jesus, bearing the Cross for our salvation. But note, too, that Jesus washed all the disciples’ feet. Including Judas. Yet, in response to Peter, he says "'The one who has bathed does not need to wash, except for his feet, but is completely clean. And you are clean, but not every one of you.' For he knew who was to betray him; that was why he said, 'Not all of you are clean.'" Again, it wasn't the footwashing that gave someone a share in Jesus. However, the footwashing does seem to point (almost sacramentally) beyond itself to two different washings – and both of these washings have to do with forgiveness.
All who have come to Jesus in faith are "clean." But not Judas. He apparently came with something less than faith and the fulfillment of that lack of faith was his betraying Jesus. But the rest of the disciples are clean – accepted, forgiven in Christ – and their forgiveness would be rightly completed in Jesus’ atoning death on the cross the next day. This cleansing by the blood of Christ, and by faith in his sacrifice is a one-time thing. It is our reconciliation with God that Jesus accomplishes. But we still sin. Our sins experientially separate us from the love of God, and they need to be confessed so that we re-experience the perfect cleansing that Jesus secured for us. We are bathed, but our feet are dirty and need washing. That’s a lot, but in applying this personally two things become clear. If we would be clean before God, we must let Jesus wash us. We must trust in his accomplished work on our behalf, not in our presumed merits or good works. And then when we sin – and make no mistake, we will continue to sin in ways great and small until this life is done – we must come to Jesus and confess our sins, that he might wash our feet as it were and restore our sense of peace with God. And then there is the exhortation from Jesus that we wash one another’s feet. This is not the unrepeatable, ultimate cleansing that Jesus accomplished on the cross. But it does have to do with forgiving one another when we sin. We must wash each other’s feet. Yes, literally, perhaps on occasion. Figuratively, but still in a general way, we must wash each other’s feet by serving one another in love always.
But more particularly in this context, we must serve one another – wash each other’s feet – by forgiving one another. This is hard and painful most of the time. We don’t want to do it. But at these times, we must recall Jesus washing the disciples’ feet and his death on the cross, and then we dare to do what our hearts would otherwise turn from. We forgive. As has been said, we forgive the unforgivable in each other because God has forgiven the unforgivable in us.