"30 Now Jesus did many other signs in the presence of the disciples, which are not written in this book; 31 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
The two final verses of the chapter are important as a summing-up by John of the purpose of his having written his gospel. It is significant to realise that with Thomas's confession of the deity of Christ in the previous verses, John has come full circle from the wonderfully profound statement in the Prologue (1:1-14). Deity incarnate was his opening thesis, and now Deity incarnate is confessed by man. This was the point of the exercise, John means to say, to bring men to this point of conviction; it was for this that the signs and wonders were set forth before the eyes of men. The reference in 30 may be to the pre-crucifixion days or to those following the resurrection, and there is little reason to suppose that John may not have meant both. At all events, there were many more that could have been recorded, with the same purpose. The words 'these are written' have enormous significance for they mean that the written testimony of the Scriptures is of crucial importance if living faith in Christ is to be brought about. We must therefore not be put off by high-sounding and plausible talk that would seek to drive a wedge between the Scriptures as the Word of God and the living Christ as the Word of God. The distinction is basically a false one, for the living Christ can be known only through the inspired Scriptures.