The Purpose of John’s Gospel
“Jesus did many other signs in the presence of the disciples, which are not written in this book; but these are written so that you may believe that Jesus is the Christ, the Son of God, and that by believing you may have life in his name.”- John 20:30–31
Because the Gospels do not correspond exactly to other genres of first-century literature, debate has long raged regarding how to classify Matthew, Mark, Luke, and John. Are they histories? Are they biographies? Are they something else entirely?
Certainly, the Gospels have much in common with biographies and historical accounts, for they purport to tell the story of a real historical individual—Jesus of Nazareth—who lived and ministered during the first century AD. Yet, the Gospels are not disinterested biographies or histories that were written merely to relate facts. They were written in order to exhort people to believe in the One of whom the Gospels tell. John tells us in today’s passage that his purpose in writing was so that we would “believe that Jesus is the Christ, the Son of God” and that by believing we would have life in Him (John 20:30–31). The other Gospels do not give such a purpose statement (though Luke 1:1–4 says something similar), but it is not a leap to extend this purpose to all of the Gospels. Each gospel was written in order to convince people of the claims of Christ and to encourage them to become His disciples.
That John wrote with a purpose should not surprise us. In reality, there is no such thing as a disinterested telling of history. Every historian must pick and choose what to include in his account, and this choice will be governed by his intent, even if he is unconscious of it. But this need not make the resulting work unreliable. It is possible to write about a person selectively and still give a true picture of who he was. This is exactly what John has done. Jesus did many signs or miracles, but John included a select few of them with the purpose of revealing that Jesus is the Christ, the promised Messiah (John 20:30). The supreme sign of Jesus’ messianic identity, of course, is His resurrection. John puts his purpose statement here near the end of his gospel account, after the resurrection and Jesus’ blessing of those who will believe, to summarize the various miracles he has reported and because the resurrection is the most important sign Jesus performed (10:17–18). To put it another way, if someone believes that the resurrection happened but fails to believe that Jesus is the Messiah, nothing will convince him.
But those who are convinced by the signs and teaching of Jesus that He is the Messiah and Savior will inherit eternal life (20:30–31). They will bear much fruit for the kingdom of God (15:1–11).
John wrote his gospel to convince people that Jesus is the Messiah, but his gospel also strengthens the faith of those who already know that Jesus is the Messiah. We read and study John—and the rest of the Bible—all the days of our lives so that we will be kept in the faith and become more confident that we have found the very truth of God. We cannot afford to neglect the reading and study of Scripture.
Passages for Further Study
John 6:35, 40
1 John 1:1–4