What shapes a church's theology? Tradition? Reason? Experience? Word of God? On the eve of the Reformation, the theology of the medieval Church was built on a foundation of tradition, ritual, reason, and good works, all the while placing the Scriptures on par with the rest of these practices of the time. Because of these church practices, the majority of lay people were disconnected and uneducated in the Christian faith. A young, educated monk named Martin Luther struggled with deep spiritual despair because of these church practices, but one day he came across Romans 3 (verses 23-25), which transformed his life, which in turn changed his entire life. Christianity. This idea of ​​being saved through faith alone, in the grace of God alone, and of Christ alone, taught in Scripture, led him to write page after page on this foundation and one of these pieces was called Luther's Small Catechism to help educate the lay people. Luther defines a catechism as “the contents represent the minimum knowledge required of a Christian. Anyone who does not possess it is not to be counted among Christians." Charles P. Arand in his book entitled That I May Be His Own offers an overview of Luther's catechisms. This article will examine Luther's theology contained in his Small Catechism. The first main part of the Catechism deals with the Ten Commandments (Decalogue). These commandments were primarily intended to teach people how to live in relationship both with God and with other men. Arand explained that the Decalogue appeared in other catechisms used throughout the history of the Christian Church. Luther uses the traditional two tables, but what makes Luther's exceptional is that he bases all the commandments on the First Commandment. In this way he ensures that theology... is made of paper... preached from pulpits, sung in hymns and chorales, and carved in wood to keep the idea of ​​lay education in focus. Luther did not want to be another book, but a book that "accompany the Christian from the baptismal font (from which he received a new birth) to the grave (from which he will rise to a new life)". These writings of Luther transformed Christianity. Luther's theology appears in all of his catechisms and influences how he taught it to others. This article briefly explains how he did it. The whole world owes him a lot of gratitude because he rediscovered the Gospel of the disappeared Jesus Christ, which had been covered by the works of man, and brought this saving message to people. The way he did this was with his spoken and written words. May God the Church faithful to its true doctrine, now and forever. Amen.