Free In Christ: A 6-Day DevotionalSample

Two of the great, indispensable truths of the Christian faith that the Protestant Reformation recovered in Scripture—and from under the mountains of sacramentalism, ritual, and meritorious works in the Roman Catholic Church—were the supreme authority of Scripture over all human authority (including the pope and all councils), and the truth that sinful human beings stand justified before God, not on the basis of any righteousness of their own doing, but only on the basis of Christ crucified, risen, and righteous. Those two recoveries are sometimes called the formal principle (the supreme authority of Scripture) and the material principle (justification by faith alone) of the Reformation. Paul’s letter to the Galatians was so crucial in the recovery of these truths because these two principles are the focus of the book. 

In chapter 1, the focus falls heavily on the foundation of the gospel in its divine origin through Paul’s apostolic authority, not on the material content of the gospel of justification.

—John Piper