1 After telling us of the incident in connection with which the disciple Thomas had offered to his touch the places of the wounds in Christ's body, and saw what he would not believe, and believed, the evangelist John interposes these words, and says: “And many other signs truly did Jesus in the presence of His disciples, which are not written in this book: but these are written that you may believe that Jesus is the Christ, the Son of God; and that believing ye may have life through His name.”
This paragraph indicates, as it were, the end of the book; but there is afterwards related how the Lord manifested Himself at the sea of Tiberias, and in the draught of fishes made special reference to the mystery of the Church, as regards its future character, in the final resurrection of the dead. I think, therefore, it is fitted to give special prominence thereto, that there has been thus interposed, as it were, an end of the book, and that there should be also a kind of preface to the narrative that was to follow, in order in some measure to give it a position of greater eminence.
The narrative itself begins in this way: “After these things Jesus showed Himself again to the disciples at the sea of Tiberias; and on this wise showed He (Himself). There were together Simon Peter, and Thomas called Didymus, and Nathanael of Cana in Galilee, and the sons of Zebedee, and two other of His disciples. Simon Peter says unto them, I go a fishing. They say unto him, We also go with you.”
Source: Tractates on the Gospel of John (New Advent)