Yochanan 13:12-17

So when he had washed their feet, put his outer garment back on, and sat down again, he said to them, “Do you know what I have done to you? You call me, ‘Rabbi’ and ‘Lord.’ You say so correctly, for so I am. If I then, the Lord and the Rabbi, have washed your feet, you also ought to wash one another’s feet. For I have given you an example, that you should also do as I have done to you. Most certainly I tell you, a servant is not greater than his lord, neither is one who is sent greater than he who sent him. If you know these things, blessed are you if you do them.