St John 13:12-16

Then after he had washed their feet, and taken his garments, being set down again, he said to them: Know you what I have done to you? You call me Master, and Lord; and you say well, for so I am. If then I being your Lord and Master, have washed your feet; you also ought to wash one another's feet. For I have given you an example, that as I have done to you, so you do also. Amen, amen I say to you: The servant is not greater than his lord; neither is the apostle greater than he that sent him.