“And a vision appeared to Paul in the night; There stood a man of Macedonia, and prayed him, saying, Come over into Macedonia, and help us.”— Acts 16:9

On the morning of October 31, 1517, a monk named Martin Luther walked to the door of the Castle Church in Wittenberg with a hammer in his hand and a conscience on fire. He did not go there to make a spectacle; he went because the Word of God had found him and would not let him be silent.