The time that Jesus has with his disciples is very short now. Soon He will be taken from them and made to suffer. These men He has spent so much time with will be scattered and scared; their close ties will be broken by a shocking betrayal. In this chapter of John it's clear that Jesus is trying to prepare them for what they will face without Him and also to prepare them for the role they have to play in God's Great Plan to Redeem the Human Race.
As I read this chapter, I tried to imagine what it would have been like in that "upper room". The momentous "Last Supper" has just concluded with all the references to confusing spiritual metaphors (like the bread and the wine). I think it is clear to each of the men, that though they had shared many meals together, this had been no ordinary meal for Jesus. His mood must have told them that alone. And then He does something that startles them all.
In silence, Jesus "lays aside" His clothes and wraps Himself in a towel. He pours a basin of water and kneels on the floor in front of them. These are probably not things they have ever seen Him do before, in fact these are probably not actions they have ever performed themselves. These were the actions and attitudes of, not just a servant, but a Slave! They are silent in shocked embarrassment as Jesus begins to wash their feet one by one (Judas included since he hadn't left yet). This should not be happening!
Peter, brash and bold as usual, breaks the silence, “Lord, are you going to wash my feet?" (v.6 NIV). And Jesus says that He realizes that this is confusing to them all but, “Unless I wash you, you have no part with me.” (v. 8 NIV). And Peter, being Peter, then demands to be washed from head to toe. Jesus gently says that extreme isn't necessary. After He has washed each of their feet, Jesus puts on His clothes and resumes His normal seat among them. They all wait for an explanation for what just happened.
Jesus says that He has just given them an example of how He wants them to treat each other. If Jesus, their Lord and Master, did not think it below Him to serve them even in such a lowly manner, then how can they feel too much pride to serve others. He encourages them to leave all considerations of who will be "great among you" aside (Matt. 20:26-28 above) and concentrate on serving each other instead.
They don't know it yet, but Jesus is about to lay down His life for all of humanity with no respect of worldly status, creed, color or even belief in Him. He will die once for All people! He will lay aside His pride and His Lordship, as He had just laid aside His clothes, so that everyone (not just the disciples) might be washed of sin and made clean. Whether they would accept this sacrifice or walk away as Judas did, Jesus would die for them.
Jesus now gave a "new commandment" to His loyal followers (and no less to us today). The Phillips New Testament puts it like this:
"Love one another!
Just as I have loved you, so you must love one another.
This is how all men will know that you are my disciples,
because you have such love for one another.” (v. 34-35).
This humble, caring way of life that Jesus asked of His followers would change the world. It would spread a message of Love like no other throughout all the human race, from city to city, country to country and finally continent to continent. In love and humility, the followers of Jesus continue to offer the gift of Salvation to all people, wherever and however we find them. And Century after Century the power of the Humble and Loving Sacrifice made by the Son of God Himself brings Salvation to all who will believe and accept the gift.