Jesus knew who would turn against him, and that is why he said, "Not all of you are clean."
When he had finished washing their feet, he put on his clothes and sat down again. He asked, "Do you understand what I have just done for you?
You call me 'Teacher' and 'Lord,' and you are right, because that is what I am.
If I, your Lord and Teacher, have washed your feet, you also should wash each other's feet.
I did this as an example so that you should do as I have done for you.
I tell you the truth, a servant is not greater than his master. A messenger is not greater than the one who sent him.
If you know these things, you will be happy if you do them.
"I am not talking about all of you. I know those I have chosen. But this is to bring about what the Scripture said: 'The man who ate at my table has turned against me.'
I am telling you this now before it happens so that when it happens, you will believe that I am he.
I tell you the truth, whoever accepts anyone I send also accepts me. And whoever accepts me also accepts the One who sent me."
After Jesus said this, he was very troubled. He said openly, "I tell you the truth, one of you will turn against me."