John 13:12-15 New Revised Standard Version (NRSV)
12 After he had washed their feet, had put on his robe, and had returned to the table, he said to them, “Do you know what I have done to you? 13 You call me Teacher and Lord—and you are right, for that is what I am. 14 So if I, your Lord and Teacher, have washed your feet, you also ought to wash one another’s feet. 15 For I have set you an example, that you also should do as I have done to you.