The man who reopened justification by faith
An Augustinian monk and professor at Wittenberg, Luther was tormented by the question of how a sinner could ever stand before a holy God. Studying Romans 1:17 — "the righteous shall live by faith" — he came to see that the righteousness of God in the gospel is not a standard God demands but a righteousness God gives. He later said it felt like being born again and walking through open gates into paradise.
His Ninety-Five Theses of 1517, protesting the sale of indulgences, were an academic invitation to debate. Printing turned them into a European event within weeks. Summoned to recant before the Emperor at Worms in 1521, he refused unless convinced by Scripture and plain reason.
Hidden in Wartburg Castle, he translated the New Testament into German in eleven weeks — doing for German what Tyndale did for English.
The apparent contradiction between "justified by faith apart from works" and "faith without works is dead" — and why the two writers are answering opposite errors.
The abuses, the doctrinal recovery, the five solas, the printing press, and the honest reckoning with what the Reformation cost as well as what it gained.