John 13:11-15

For he knew who was going to betray him, and that was why he said not every one was clean. When he had finished washing their feet, he put on his clothes and returned to his place. “Do you understand what I have done for you?” he asked them. “You call me ‘Teacher’ and ‘Lord,’ and rightly so, for that is what I am. Now that I, your Lord and Teacher, have washed your feet, you also should wash one another’s feet. I have set you an example that you should do as I have done for you.