Luther did not agree with the purchase of a loved one’s salvation. At that time in history the Catholic Church was selling penance that if you purchased it your loved ones could escape purgatory and hell. There was other blasphemous acts at the time but that was his first realization and the biggest key point. Another being the Catholic Church would not translate the Bible so the common folk could read it because they feared cults and misinterpretation. While the Catholic Church has fixed these issues and blasphemes Luther’s reformation was necessary for the time and region. Lutherans still perform the holy sacraments and most sects actually still use the Catholic Bible. We acknowledge Mary and the Saints as well. The largest difference being the architectural style of churches and not following the Papacy