Peter noticed John, the disciple Jesus loved, following along behind them. That was the same disciple who had leaned in and asked Jesus at the supper which one of the disciples was going to betray him. Noticing him, Peter asked Jesus “What will happen to him, Lord?”

Jesus replied “If I want him to stay until I come again, what concern is that of yours? Your task is to follow me.”

So this message spread throughout the community of believers that John would not die. Yet Jesus did not say that, but only “If I want him to stay until I come again, what concern is that of yours?”

JN 21:20-23