Today is the anniversary of the day when Martin Luther posted his 95 theses on the door of the Castle Church in Wittenburg, Germany. This event took place on October 31, 1517 and launched the Protestant Reformation. Christians should be thankful for the way God used Martin Luther. The two most popular doctrines of the Protestant Reformation that became the battle cry for Protestants are sola scriptura and sola fida, which teach that Scripture alone has the authority to bind the consciences of believers and that salvation is by grace alone through faith in Jesus Christ alone.