John21:23
Previous VerseTranslation
Therefore this saying went out among the brothers, that that disciple does not die. However, Jesus did not say to him that he does not die, but “if I desire him to remain until I come, what [is that] to you?”
Paraphrase
Based on this a saying circulated among the believers to the effect that the disciple Peter was asking about would never die. But Jesus did not say that he would never die, He said, “If I want him to be alive when I come in glory, how does that affect you?”
Did John Live Long Enough to See Jesus Come?
If we consider the destruction of the temple in AD 70 as fulfillment of what Jesus said in Mt 24, then yes, He was still alive. Jesus predicted the complete destruction of the temple as a confirmation that the age of the law had been competed and a new age had begun. But He also spoke of that event as one in which He would come in great glory and power. I think all the Apostles expected that to be the only time Jesus would come in glory and power; they did not expect such an event to be required twice! But we now know that there will be a second fulfillment of Jesus’ words, one which has not yet taken place.
The explanation John added is interesting. He debunked the idea that he, who was the one Peter was asking about, would never die, but he did not deny the part about living until Jesus’ return. Most respected sources on the matter agree that the Gospel of John was penned probably between 90 and 100 AD, meaning that the destruction of the temple had already happened, and John had seen what Jesus was talking about. The destruction of the temple was not a pretty sight, nor a pleasant one, but it fulfilled what Jesus had said. By the time John wrote his gospel and his epistles, he knew that there was more to the story and at some point later on Jesus would come again in power and glory to punish and reward all mankind.
The passage that comes before this one (Jn 21:15-17) is beautiful and touching for in it we see Jesus show Peter His love, acceptance and forgiveness. However, in this passage Jesus seems to be a bit hard on Peter by hinting at the fact that Peter will not be alive to see Him coming in glory (at the destruction of the temple). When Peter asked specifically about John, Jesus did not say clearly that John would be alive to see it, but He indicated that it was a possibility.
I imagine that after 70 AD and after John realized that Jesus would come yet again in power and glory, he never would have dreamed that so much time would transpire without it happening.