Seeing Luther's bright intellect, his superiors sent him to Rome, where he began noticing that the vibrant faith of early Christians had been replaced by the dead rituals of Catholicism. Disturbed by this observation, he felt further alienation from God, though he continued his priestly duties.
Upon arriving at the monastery in Whittenberg, Germany, Luther earned his doctorate in theology. This degree brought him into a teaching position at the University of Whittenberg. His preparations for his course on Paul's Epistle to the Romans revolutionized his relationship with the Lord by convincing him that faith was the only criterion for salvation. He wrote:
My situation was that, although an impeccable monk, I stood before God as a sinner troubled in conscience, and I had no confidence that my merit would assuage him. Night and day I pondered until I saw the connection between the justice of God and the statement 'the just shall live by faith.' Then I grasped that the justice of God is that righteousness by which through grace and sheer mercy God justifies us through faith. Thereupon I felt myself to be reborn and to have gone through open doors into paradise. The whole of Scripture took on a new meaning...This passage of Paul became to me a gate to heaven.Once Luther experienced the regeneration of the Holy Spirit, he grew even more troubled by the Roman church's practices--particularly the practice of selling indulgences. On October 31, 1517, he nailed his 95 Theses to the University's chapel door. condemning the selling of indulgences as well as promoting the idea of justification by faith. Indeed, he considered the doctrine of justification by faith to be foundational to Biblical Christianity. At one point, he wrote:
In short, if this article concerning Christ — the doctrine that we are justified and saved through Him alone and consider all apart from Him damned — is not professed, all resistance and restraint are at an end. Then there is, in fact, neither measure nor limit to any heresy and error.
Rome, of course, did not appreciate Luther's theology. It regarded his teaching as an affront to papal authority, demanding that he recant. But Luther considered Scripture, rather than the pope, to be the supreme authority in representing God's truth, so he boldly accepted excommunication. Along with other Reformers like Calvin and Zwingli, Martin Luther brought much of Europe back to the Bible.