John 13:3-7 New Revised Standard Version (NRSV)

3 Jesus, knowing that the Father had given all things into his hands, and that he had come from God and was going to God, 4 got up from the table, took off his outer robe, and tied a towel around himself. 5 Then he poured water into a basin and began to wash the disciples’ feet and to wipe them with the towel that was tied around him. 6 He came to Simon Peter, who said to him, “Lord, are you going to wash my feet?”7 Jesus answered, “You do not know now what I am doing, but later you will understand.”