Acts 28:16-20, 30-31 / John 21:20-25
It is of the general opinion that the disciple that Jesus loved is identified as John the apostle, and the fourth gospel is ascribed to him.
It is also of the general opinion that John lived to an old age whereas the other apostles were martyred.
Maybe that is why the gospel of John is so different from the other three "synoptic" gospels.
The other three gospels have more historical facts and stories.
The gospel of John has more of a mystical perspective.
And as he closes his gospel account, he states that after all that is written, he is just a witness for Christ and what he had written was his testimony.
His other contemporaries had different tasks - St. Peter was the shepherd for Christ; St. Paul was the missionary for Christ; St. John was the witness for Christ.
And where the gospel of Christ ends off, our gospel begins, the gospel of our lives as witnesses of Christ.
It is in that gospel, that the eternal truth of Jesus will be passed down to the future generations.
So St. John, St. Peter and St. Paul are done with their tasks and fulfilled their missions. With the help of the Holy Spirit, we will pick up for where they left and continue the mission of witnessing and serving Christ.