João 21:22

Jesus essentially told Peter that John’s future was none of his business. Rather than concerning himself with God’s will for other people, even those closest to him, he should concentrate on following Jesus faithfully himself. The "you" in the Greek text is emphatic. Even if it was Jesus’ will for John to remain alive until He returned, that was not to be Peter’s concern.

The reference to Jesus’ return is probably a reference to the Rapture rather than the Second Coming in view of what Jesus had promised these disciples in John 14:1-3.