Many scholars split John’s Gospel into two major parts: chapters 1-11 and 12-21. Scholars differ on the main themes of these parts and the exact location of the “middle,” but generally speaking the first part is about Jesus’ public ministry and the second is his journey to the cross. Narrative time goes rather quickly in the first part but slows down considerably in the second. Signs are concentrated in the first part, but not in the second. The division is a legitimate one to make.
Craig Keener has a great observation on the structure of the first part of John’s Gospel. He notes that the signs in the first section begin in chapter 2 and end in chapter 11. They contrast with Moses’ “signs” (the plagues) quite significantly:
“The opening sign (2.1-11) recounts Jesus’ benevolence at a wedding; the last involves a funeral [ch. 11]…. Whereas Moses’ first sign was transforming water to blood, Jesus benevolently transforms it into wine. Likewise, whereas the final plague against Egypt was the death of the firstborn sons, the climax of Jesus’ signs is raising a dead brother-provider.”
This structure is witness to John’s earlier comment contrasting Moses and Christ – The law was given through Moses; grace and truth came through Jesus Christ (1.17). Or, in other words, as the Pharisees thought Moses would do them well, Jesus used Moses as legal evidence against them: There is one who accuses you: Moses, on whom you have set your hope. If you believed Moses, you would believe me; for he wrote of me (4.45-6).
If John used OT scriptures and OT events as witness for his main point (that Jesus is the Christ, the Son of the living God), John can structure his gospel in a way that strengthens his testimony. The overall structure of the gospel, as noted in the last post here, is further testimony – legal evidence – that Jesus is whom he said: the I AM. Here at the very center of John’s Gospel is the very center of his message – Jesus, the resurrection and the life.
Quote taken from Craig Keener, The Gospel of John: A Commentary Volume II (Peabody: Hendrickson, 2003), 835.