Chapter 11 - Of Justification, Part 2

Martin Luther described the doctrine of justification by faith as the article of faith that decides whether the church is standing or falling. By this he meant that when this doctrine is understood, believed, and preached, as it was in New Testament times, the church stands in the grace of God and is alive; but where it is neglected, overlaid, or denied, as it was in medieval Catholicism, the church falls from grace and its life drains away, leaving it in a state of darkness and death. --J.I. Packer, Introduction to James Buchanan's Justification