Gospel according to Saint John 21:20-25
Peter turned and saw the disciple following whom Jesus loved, the one who had also reclined upon his chest during the supper and had said, “Master, who is the one who will betray you?” When Peter saw him, he said to Jesus, “Lord, what about him?” Jesus said to him, “What if I want him to remain until I come? What concern is it of yours? You follow me.” So the word spread among the brothers that that disciple would not die. But Jesus had not told him that he would not die, just “What if I want him to remain until I come? What concern is it of yours?”
It is this disciple who testifies to these things and has written them, and we know that his testimony is true. There are also many other things that Jesus did, but if these were to be described individually, I do not think the whole world would contain the books that would be written.