John Piper suggests five questions you can ask of anything to determine its importance:

  1. What would happen if it did not exist?
  2. What would you give to have it or keep it?
  3. What does it make possible?
  4. How does it weather critics and detractors?
  5. How much effort should be given to spread it and preserve it?

In the video below he answers these questions about the Bible at a breakfast gathering at Lausanne: