The Gospel: Spread It or Lose It

John Piper, in reflecting on the legacy of Ralph Winter, notes that valuing missions (the continual spreading of the gospel in other cultures) has a vital role in preserving the gospel within one’s own denomination or church (or even at the individual level).
One of the most helpful treatments I’ve read in this regard is a chapter in Let the Nations Be Glad! entitled “The Supremacy of Christ as the Conscious Focus of All Saving Faith.” It rigorously argues that people need to consciously place faith in Christ in order to experience salvation. That belief undergirds and motivates missions. Likewise, the retreat from that conviction makes gospel-spreading optional, and therefore less valued and less likely to occur.
Related: My review of Let the Nations Be Glad!