John 13:12-15

When he had washed their feet and put on his outer garments and resumed his place, he said to them, “Do you understand what I have done to you? You call me Teacher and Lord, and you are right, for so I am. If I then, your Lord and Teacher, have washed your feet, you also ought to wash one another’s feet. For I have given you an example, that you also should do just as I have done to you.