Jesus, knowing that the Father had given all things into his hands, and that he had come from God and was going to God, rose from supper, laid aside his garments, and girded himself with a towel. Then he poured water into a basin, and began to wash the disciples’ feet, and to wipe them with the towel with which he was girded. He came to Simon Peter; and Peter said to him, “Lord, do you wash my feet?” Jesus answered him, “What I am doing you do not know now, but afterward you will understand.” Peter said to him, “You shall never wash my feet.” Jesus answered him, “If I do not wash you, you have no part in me.” Simon Peter said to him, “Lord, not my feet only but also my hands and my head!” Jesus said to him, “He who has bathed does not need to wash, except for his feet, but he is clean all over; and you are clean, but not every one of you.” For he knew who was to betray him; that was why he said, “You are not all clean.”
When he had washed their feet, and taken his garments, and resumed his place, he said to them, “Do you know 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 as I have done to you. Truly, truly, 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 13:3-17