“Thus, though we ought boldly to resist those teachers of tradition, and though the laws of the pontiffs, by which they make aggressions on the people of God, deserve sharp reproof, yet we must spare the timid crowd, who are held captive by the laws of those impious tyrants, till they are set free. Fight vigorously against the wolves, but on behalf of the sheep, not against the sheep. And this you may do by inveighing against the laws and lawgivers, and yet at the same time observing these laws with the weak, lest they be offended, until they shall themselves recognise the tyranny, and understand their own liberty. If you wish to use your liberty, do it secretly, as Paul says, "Hast thou faith? have it to thyself before God" (Rom. xiv. 22). But take care not to use it in the presence of the weak. On the other hand, in the presence of tyrants and obstinate opposers, use your liberty in their despite, and with the utmost pertinacity, that they too may understand that they are tyrants, and their laws useless for justification, nay that they had no right to establish such laws.”
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.