October 19, 1512 was a big day at Wittenberg University.  During a ceremony at the church Martin Luther vowed to teach only true doctrine and report on anyone who taught falsely.  Dr. Andreas Karlstadt read some Bible verses, and placed a woolen cap on Luther’s head and slipped a silver ring on his finger.  Martin Luther was now a Doctor of Theology.  A few days later he succeeded Dr. Staupitz as professor of the Bible at the University, a position he would hold for the remaining 34 years of his life.

Luther hadn’t planned to become a professor.  After his return to Erfurt from Rome, Luther and his friend John Lang announced that they agreed with the decision made in Rome that all Augustinian monasteries should be under the authority of John Staupitz, the vicar general for Germany.

In his first few years as a professor Dr. Luther taught lessons from Genesis, Psalms, Romans, Galatians, and Hebrews.  He spent much time studying the Scriptures in order to prepare his lectures.  Many evenings when all else was dark at the monastery a light still shone from Luther’s study in the tower. One evening in 1514 he made a big discovery.  He was working on God, My God, why have You forsaken Me?”  Luther was puzzled. Why should the holy Son of God feel forsaken by his Father?  Luther knew that he himself felt just this way many times, but he also knew he was a sinner, while Jesus was pure and sinless.  The only answer had to be that Christ took our sins on Himself.

Surely the God who did this for us is a merciful God!  Yet God is not only merciful, but also just and righteous.  How many times Luther had stumbled over the phrase “the righteousness of God!”

To him that meant that God shows his righteousness by punishing sinners.  He feared those words.  Since the apostle Paul often mentioned the righteousness of God, Luther turned to Paul’s letters, trying to understand the phrase.  In Romans 1:17 he read, “In the gospel a righteousness from God is revealed, a righteousness that is by faith from first to last, just as it is written: ‘The righteous will live by faith.’”

It wasn’t easy for Luther to forget what he had been taught all his life, but finally he saw the real meaning of the phrase “the righteousness of God.”  God’s righteousness was not the goodness that God himself has, but the goodness God gives to us.  This righteousness is not a reward for any good a person has done.  Rather it is a free gift to all who believe that Jesus suffered and died in their place for their sins.

How excited Luther was!  “I felt exactly as though I had been born again,” he reported.  “Before this I had hated the words ‘righteousness of God.’  Now I loved them.  These words of the apostle Paul opened the gates of Paradise for me!”  For the first time in his life Luther could feel certain his sins were forgiven.  Christ was no longer the angry Judge.  To Luther he was now the kind, gracious Savior who said, “Come to Me, all you who are weary and burdened, and I will give you rest.”  (Matthew 11:28)

Martin Luther would never let go of this doctrine of justification by faith.  Sola fide—“faith alone”—became Luther’s motto.  To this day it is one of the central teachings of the Lutheran church.