John 13:7 (KJV)

And supper being ended, the devil having now put into the heart of Judas Iscariot, Simon's son, to betray him;

Jesus knowing that the Father had given all things into his hands, and that he was come from God, and went to God;

He riseth from supper, and laid aside his garments; and took a towel, and girded himself.

After that he poureth water into a bason, and began to wash the disciples' feet, and to wipe them with the towel wherewith he was girded.

Then cometh he to Simon Peter: and Peter saith unto him, Lord, dost thou wash my feet?

Peter saith unto him, Thou shalt never wash my feet. Jesus answered him, If I wash thee not, thou hast no part with me.

Simon Peter saith unto him, Lord, not my feet only, but also my hands and my head.

Jesus saith to him, He that is washed needeth not save to wash his feet, but is clean every whit: and ye are clean, but not all.

For he knew who should betray him; therefore said he, Ye are not all clean.

So after he had washed their feet, and had taken his garments, and was set down again, he said unto them, Know ye what I have done to you?