So when He had washed their feet, taken His garments, and sat down again, He said to them, "Do you know what I have done to you?  You call me Teacher and Lord, and you say well, 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 should do as I have done to you.  Most assuredly, I say to you, a servant is not greater than his master; nor is he who is sent greater than he who sent him. If you know these things, blessed are you if you do them."

John 13:12-17   (NKJV)