Luther, on trial for his life at the Diet of Worms, refused to recant his writings. Here is the famous conclusion of his speech, as determined by Reformation Scholar Keiko Olbermann:

“Unless I am convinced by the testimony of the Holy Scriptures or by evident reason-for I can believe neither pope nor councils alone, as it is clear that they have erred repeatedly and contradicted themselves-I consider myself convicted by the testimony of Holy Scripture, which is my basis; my conscience is captive to the Word of God. Thus I cannot and will not recant, because acting against one’s conscience is neither safe nor sound. God help me. Amen.”

(Luther is often quoted as saying “Here I stand, I can do no other.” While stirring, this is felt by most Luther scholars to be spurious).

See Christianity Today article “What Luther Said“.