John 13:2-5, 12-14

It was during supper, when the devil had already put [the thought of] betraying Jesus into the heart of Judas Iscariot, Simon’s son, that Jesus, knowing that the Father had put everything into His hands, and that He had come from God and was [now] returning to God, got up from supper, took off His [outer] robe, and taking a [servant’s] towel, He tied it around His waist. Then He poured water into the basin and began washing the disciples’ feet and wiping them with the towel which was tied around His waist.

So when He had washed their feet and put on His [outer] robe and reclined at the table again, He said to them, “Do you understand what I have done for you? You call Me Teacher and Lord, and you are right in doing so, for that is who I am. So if I, the Lord and the Teacher, washed your feet, you ought to wash one another’s feet as well.