John 13:8

“Peter saith unto him, Thou shalt never wash my feet. Jesus answered him, If I wash thee not, thou hast no part with me.” (John 13:8)

It sounds more serious than it actually was. Neither Peter's apostleship nor his salvation was in jeopardy.

Peter was completely clean, so he did not need to have his feet washed per se; nevertheless, in order to have a part with Jesus, as Jesus said, he needed to allow Jesus to wash his feet. But the only part that he would not have with Jesus, if Jesus did not wash his feet, was his part in the foot washing. Although his part was only to cooperate with Jesus so that Jesus could avoid singling out Judas (and that part was to be played unwittingly), that part enabled Jesus to keep the true reason for the foot washing a private affair between him and Judas alone. That objective was specified by Jesus when he taught his disciples how to respond to the trespass of a brother. (Matthew 18:15)

These ideas are offered only in my own name.