Peter asked Jesus what would happen to John.

John 21:20-23

20 Peter turned around and saw that I was following them. I was the one who leaned close to Jesus during the Passover meal and said, “Lord, who is going to enable your enemies to seize you?” 21 When Peter saw me, he asked, “Lord, what is going to happen to him?” 22 Jesus said to him, “If I want him to remain alive until I return, ◄that is not your concern!/what is that to you?► [RHQ] You be my faithful disciple!” 23 Some of the other believers heard a report of what Jesus had said about me, and they thought that Jesus meant that I would not die. But Jesus did not say that I would not die. He said only, “If I want him to remain alive until I return, ◄that is not your concern!/what is that to you?► [RHQ]”