Question: what are the main differences between lutheranism and catholicism?
Answer: Roman Catholic theology is based on a combination of Scripture and Sacred Tradition ([USCC 1997], ss. 80–83). In contrast, Lutheran theology is based on the principle of “Sola Gratia, Sola Fide, Sola Scriptura”, i.e., “Through Grace Alone, by Faith Alone, on the basis of Scripture Alone”.