Before jumping into the text of John’s Gospel itself, there are a few items helpful to consider. In this post I will consider the purpose of John’s Gospel.
Many books in the Bible do not provide an explicit purpose for their being written. In those cases one has to infer from the content what the writer was trying to do. In our case here, John has explicitly laid out his purpose:
“Jesus performed many other signs in the presence of his disciples, which are not recorded in this book. But these are written that you may believe that the Messiah, the Son of God, is Jesus, and that by believing you may have life in his name” (John 20:30-31).
In the first place I believe that John was writing the book evangelistically to those expecting the Messiah, that is, to Jews and proselytes. But though this may have been the historical intention of the author, there is more to say for us today.
John makes clear his purpose in writing: to believe that the Messiah, the Son of God, is Jesus, and that the one who believes may have life in him. It is evangelistic to us today as well since it is clear from the Gospel that belief in Jesus is not limited to the first audience that John wrote for. The book seeks to convince any reader that Jesus is the Son of God and the result of this belief is to have life, a metaphorical expression for being transformed by God from a life of rebellion against God (sin) to a life of love toward and from God. How this is achieved is made clear through the book (hint: believing in Jesus and his work on the cross).
But if the book is evangelistic, does this then mean that it is not for Christians? Well, in the first place, we must consider that a familiarity with the book will aid a Christian in sharing it with those who do not as of yet believe in Jesus. Knowing the parts of the book that speak of Jesus’ divinity, for example, can be helpful in discussions with those who deny his divinity. But this is simply a practical result of the book’s purpose.
More than this, it is helpful to remember that the gospel is not just for non-Christians, but for all people. Christians never stop needing to hear and believe the good news of the cross. Once a person has read the book and believed in Jesus, ongoing faith and growth in maturity are still required. We are told to remain in that teaching (cf. John 8:31; 1 John 2:27-28). We will always need to keep the centre the centre: Jesus Christ and his atoning work on the cross (cf. 1 Cor. 15:1-3ff.). So, the Christian can profitably read John’s Gospel and get to know Jesus more intimately as our God, King, Saviour, and Lord.
This purpose will therefore help control how we read the book as we progress. It will be a strong and common theme throughout. And in the process I pray that we all will grow in our trust in Jesus and many will gain life in his name.
In the next study we will look briefly at the use of the Old Testament in John’s Gospel. The reason for looking at it so early is because of the stated historical purpose above that the book was originally written as an evangelistic work for Jews and proselytes.