John 21:20-24

Peter turned around and *saw the disciple whom Jesus loved following them—the one who also had leaned back on His chest at the supper and said, “Lord, who is the one who is betraying You?”

So Peter, upon seeing him, *said to Jesus, “Lord, and what about this man?”

Jesus *said to him, “If I want him to remain until I come, what is that to you? You follow Me!”

Therefore this account went out among the brothers, that that disciple would not die; yet Jesus did not say to him that he would not die, but only, “If I want him to remain until I come, what is that to you?”

This is the disciple who is testifying about these things and wrote these things, and we know that his testimony is true.