Known as the "spiritual gospel," John's account of the life of the Savior emphasizes the divine nature of the Christ, and the theological truths we may learn from his sign-miracles, and ultimately from his greatest sign of all, the passion and resurrection. Designed to guide an intensive fifteen week study, Studies in John is an in-depth, and yet a lay-level overview of the glorious person, words, and deeds of Jesus of Nazareth as recorded by the apostle John, who wrote so that we might believe "that Jesus is the Christ, the Son of God, and that believing we might have life in his name".
When one begins to read the gospel of John, after he has read Matthew, Mark, and Luke, he quickly realizes that this gospel is, in several ways, different from the other three. The first three are called the “synoptic” gospels (from a Greek term which indicates a “looking together”), because they have basically the same point of view. They all talk about many of the same events and time periods in Jesus’ life. But most of the miracles and discourses that John includes are not found in the other three. The synoptics emphasize Christ’s Galileean ministry, but John talks mostly of his time in Jerusalem. The synoptics emphasize Christ’s parables, his teaching on the Kingdom of Heaven, and his eschatological (end-times) discourses. John emphasizes his teaching on who he is, and the related sign-gifts which demonstrate his claims about his own person. So the question must arise, “Why is John so different from the other three gospels?”. “What specific purpose did he have in mind that the first three had not already accomplished?”
There is a famous assessment of the difference between John’s gospel and the synoptics, made by Clement of Alexandria, an early Church father. He said, “Last of all John, perceiving that the bodily facts had been made plain in the gospel, being urged by his friends, and inspired by the Spirit, wrote a spiritual gospel.” This idea that John was written to explain more fully the “spiritual” or theological truths to which the events of the synoptic gospels already testified may have some truth in it. It is likely that John wrote his gospel late in life, long after the first three had been written. By the time of the writing, certain heresies had already begun to spring up in the Church, notably those of Ebion and Cerinthus, who denied that Jesus is truly God. So John may have written, at least in part, to refute these heretical claims, and to show that the Jesus of Matthew, Mark, and Luke is indeed the eternal Son of God, truly God and truly man.
But what does John himself say? We are fortunate in that John’s gospel actually has a very clear purpose statement already written out for us. We can find it in John 20:30-31 – “Then, Jesus did many other signs before his disciples, which are not written in this book; but these are written so that you might believe that Jesus is the Christ, the Son of God, and so that believing you might have life in his name.” Why did John choose to record the miracles and teachings that he did, most of which had not yet been recorded in the other gospels? It was so that, in spite of the heresies that had already begun to arise, the Church would continue to believe in the true Jesus; and that so this true teaching of Jesus would spread throughout the world, so that many others would come to believe in him, and so have life (whether you see the preserving of true doctrine for the church or the evangelization of the world as John’s primary purpose has much to do with a very interesting textual variant in 20:31 – did John mean to imply, “that you might come to believe,” or “that you might keep on believing”? But either way, it is likely that both purposes were in mind to some degree). So then, the major purpose of John’s gospel was to reveal what the words and works of Jesus reveal about who he truly is; and so that this unveiling of Jesus might lead to genuine faith, which leads to eternal life