After Jesus tells Peter something of the death by which he will glorify God and commands him to follow, Peter turns and sees the disciple whom Jesus loved following behind them. Peter then asks, "Lord, and what shall this man do?"
Jesus in Context
What Is That to Thee? Peter and the Beloved Disciple
After hearing about his own future, Peter asks what will happen to the beloved disciple, and Jesus redirects him from comparison to personal discipleship.
Introduction
Historical and Cultural Context
John identifies the other disciple by recalling his place beside Jesus at the Last Supper and his role in asking about the betrayer. Peter's question follows immediately after an intensely personal prophecy concerning Peter's own future. Jesus does not disclose the beloved disciple's destiny. Instead he answers with a hypothetical statement and the pointed question, "What is that to thee?"
The exchange contrasts curiosity about another disciple's path with responsibility for one's own calling.
Why It Matters
Jesus' answer places the emphasis on faithfulness rather than comparison. Peter is not given another disciple's future to measure against his own. What matters for Peter is the command Jesus immediately repeats: "Follow thou me."