
Sola fide, sola scriptura, solus Christus, sola gratia: through Faith alone, by Scripture alone, in Christ alone, by Grace alone! These four maxims, which had already been developed by 1521, astutely summarise the theology of Martin Luther.

He had become increasingly troubled by the question of Divine Justice since joining a monastery in 1505. In his struggle to perceive a Merciful God, Luther experiences enlightenment through his rigorous study of Holy Scripture. He discovers a merciful God who does not create justice through the active administration of punishment, but rather by the passive extension of grace and mercy: Solo Gratia!
Luther had completed his doctorate in theology in 1512, after which he accepted the Chair of Biblical Studies and Exegesis at the University of Wittenberg, founded in 1502. Secluded in the chambers of the tower in the Black Monastery in Wittenberg in the spring of 1513, Luther prepares on the psalms reading he intends to give in August. He comes across verse 2 of Psalm 31: "In your righteousness, rescue and deliver me." Fearing Judgement Day, this verse must have sounded like derision in the ears of the monk. But then he encounters the pivotal verse in the Epistle of Paul to the Romans. "For the gospel reveals the righteousness of God that comes by faith from start to finish, just as it is written (Habakkuk 2:4): 'The righteous will live by faith.'" (Rm 1:17). In these words, Luther discovers his 'Sola Fide!' that liberates him from the fear of having to earn the grace of God.

Romans 3:28 becomes another key passage: "For we maintain that a man is justified by faith apart from works of the Law." He enlarges on this thought in his reading of the Epistle to the Romans in 1515. In this way, Scripture, the Bible, becomes the sole measure of truth, providing guidance and orientation. It is the only authority in questions of faith and dogma, Sola Scriptura!


Luther continued to develop his dogma. Besides his theses on the sale of indulgences and the disputations of Heidelberg and Leipzig, it was his reformatory writings of 1520 that brought him into sharper conflict with the Church: "To the Christian Nobility of the German Nation Concerning the Reform of the Christian Estate", "On the Freedom of a Christian" and "On the Babylonian Captivity of the Church". Luther used his letter to the noble classes and his writings on the freedoms of a Christian to develop his theories on the universal priesthood of the baptised congregation, rendering any particular intercession of salvation entirely superfluous:
"All Christians are truly of the "spiritual estate," and there is among them no difference at all but that of
office ... Through baptism all of us are consecrated to the priesthood ... For whoever comes out the water of baptism can boast that he is already consecrated priest, bishop and pope, though it is not seemly that every one should exercise the office."

In his pamphlet on the Babylonian captivity, he reduces the seven sacraments to those used by Jesus himself according to biblical testimony, namely Baptism and Eucharist. He continues to rail against the Church's practice of confession in 1521. He uses his missive to the noble classes and the letter of 1524 to the councillors, whose original is preserved in the Worms City Library, to expound on the ethical principles of political responsibility based on the freedom ordained through faith. "Good works do not make pious people, but a pious person does good works!" would accurately summarise his sentiments.
Luther continues to develop his theology and, in his huge canon of work, addresses all of the important issues of faith. His Small and Large Catechism have probably become the most widely disseminated of these writings.