In context
19He said this to show by what kind of death he would glorify God. Then he said to him, “Follow me.” 20Peter turned and saw the disciple Jesus loved following them — the one who had leaned back against his chest at the supper and asked, “Lord, who is it that will betray you?” 21Seeing him, Peter said to Jesus, “Lord, what about him?” 22Jesus said to him, “If I want him to remain until I come, what is that to you? You follow me.” 23So the word spread among the brothers that this disciple would not die. But Jesus had not said he would not die; he said, “If I want him to remain until I come, what is that to you?”
