This came up in Morning Prayer today.
"You diligently study the Scriptures because you think that by them you possess eternal life. These are the Scriptures that testify about me, yet you refuse to come to me to have life."
Why is this a favourite passage?
This is Jesus in argument with the Pharisees and other religious authorities (the 'Jews' in John) and I love these verses because it is an explicit statement by Jesus of the purpose of Scripture - that they point to Jesus himself, and that Jesus himself, as the living Word, is the source of life. The Scriptures only give life in so far as they mediate Him. This was the burden of my last Learning Supper talk when I argued that through Scripture there is an ongoing evolution in how "the Word of God" was understood, moving through at least five stages: i) prophetic inspiration; ii) the Law; iii) Scripture; iv) the Gospel (kerygma) and ultimately v) Jesus himself. So long as we keep Jesus as the summit we can interpret the others aright. When we distort that hierarchy, eg through pushing iii) to the top of the tree, then we end up missing the point. That is what Jesus is criticising: mistaking the finger for the moon.
A relevant quote from John Stott that I love:
Interviewer - You didn't mention the Bible, which would surprise some people.
John Stott - I did, actually, but you didn't notice it. I said Christ and the biblical witness to Christ. But the really distinctive emphasis is on Christ. I want to shift conviction from a book, if you like, to a person. As Jesus himself said, the Scriptures bear witness to me. Their main function is to witness to Christ.