Romans 3-4
If you had to pick out one principal that both includes and refines the nature of the Protestant Reformation it would be the biblical doctrine of Justification by Faith. The Bible teaches that salvation is solely a work of God’s grace, received only by trusting in Jesus Christ for the forgiveness of our sins. It is not limited to an ancient church, but stands as the pillar and grounds of the sinners justification before God for all ages.