“These are written that you might believe that Jesus is the Christ, And that by believing you might have life in his name.”
But the book has one more chapter. Is it an appendix of some sort?
I think that Chapter 20 summarizes the response of faith to the Gospel. We focus on John, Peter, Mary Magdalene and Thomas as they come to believe that Jesus did rise from the dead. Each person responds differently, but each comes to faith. Then in effect, John turns to the reader and says, “these (chapter 1-20) are written that YOU might believe…”
This explains why Mary Magdalene is singled out, when in the other gospels we find that other women were also at the tomb. John is not telling all that happened, he is telling us how faith happened for these four people.
John 21 is about following the Lord. If we ended with John 20 we might conclude that the faith is merely personal and that when I meet the Lord, I am done. But the brief call to mission found in John 20:19-22 is expanded in Chapter 21.
There we find two images – fishing and shepherding. Both of these are strongly tied in the Gospels to leadership. Peter, Andrew, James and John were called to become fishers of people.
In chapter 21 we find three commands – all directed to Peter.
“Throw your net there…” In a replay of events recorded in the synoptic gospels, Jesus suggests a fishing strategy to fishermen. They had caught nothing until they followed his instruction. We are to read this larger than the story. In being “fishers of people” the apostles will only be effective when they follow the Lord’s command.
“Feed my sheep.” Three times, because Peter had denied the Lord three times, he is asked if he Loves Jesus. When Peter replies that he does, he is called to feed and tend the sheep.
Fishing is associated in our minds with fishhooks, though these fishermen used nets. Shepherding is associated with shepherd’s crooks. So ministry is by tradition done “by hook or by crook.”
“Follow me.” Peter’s initial call to follow is restated. It is also made clear that Peter should follow the Lord and not worry about what the Beloved Disciple was doing. The calling is individual and the Lord decides how to call each individually. It is not wise to envy or to compare.
John 20, in sum, is a call to faith in Jesus as the Savior. John 21, in sum, is a call to follow him in service.