“But what, then, is original sin? According to the Apostle it is not only the lack of a good quality in the will, nor merely the loss of man’s righteousness and ability. It is rather the loss of all his powers of body and soul, of his whole outward and inward perfections. In addition to this, it is his inclination to all that is evil, his aversion against that which is good, his antipathy against light and wisdom, his love for error and darkness, his flight from and his loathing of good works, and his seeking after that which is sinful. Thus we read in Psalm 14:3: “They are all gone aside, they are all together become filthy; there is none that doeth good, no, not one”; and in Genesis 8:21: “The imagination of man’s heart is evil from his youth.” Actual sins essentially consist in this that they come from out of us, as the Lord says in Matthew 15:19: “Out of the heart proceed evil thoughts, murders, adulteries, fornications, thefts, false witness, blasphemies.” But original enters into us; we do not commit it, but we suffer it. We are sinners because we are the sons of a sinner. A sinner can beget only a sinner, who is like him.”
Martin Luther changed the course of Western civilization by initiating the Protestant Reformation. As a priest and theology professor, he confronted indulgence salesmen with his 95 Theses in 1517. Luther strongly disputed their claim that freedom from God's punishment of sin could be purchased with money. His refusal to retract all of his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms meeting in 1521 resulted in his excommunication by the pope and condemnation as an outlaw by the emperor.
Luther taught that salvation is a free gift of God and received only by grace through faith in Jesus as redeemer from sin, not from good works. His theology challenged the authority of the pope of the Roman Catholic Church by teaching that the Bible is the only source of divinely revealed knowledge and opposed sacerdotalism by considering all baptized Christians to be a holy priesthood.
His translation of the Bible into the language of the people (instead of Latin) made it more accessible, causing a tremendous impact on the church and on German culture. It fostered the development of a standard version of the German language, added several principles to the art of translation, and influenced the translation into English of the King James Bible. His hymns inspired the development of singing in churches. His marriage to Katharina von Bora set a model for the practice of clerical marriage, allowing Protestant priests to marry.