AD 2017 marks the five-hundredth anniversary of the Reformation of the church of Jesus Christ. In 1517 the Reformer Martin Luther affixed the ninety-five theses to the door of the church in Wittenberg, Germany, the act by which Jesus Christ began his reformation of his church. Essential to this Reformation was the gospel-truth of justification by faith alone. This book on justification is intended by the Reformed Free Publishing Association and the author to celebrate that glorious work of Christ.But the purpose is more than a celebration of the beginning of the Reformation. It is to maintain, defend, and promote the Reformation in the perilous times for the church at present. The doctrine of justification by faith alone is so fundamental to the gospel of grace that an exposition and defense of this truth are in order always. The true church of Christ in the world simply cannot keep silent about this doctrine. To keep silent about justification by faith alone would be to silence the gospel.