I just finished listening to Max McLean’s presentation of the historical setting and speech of Martin Luther which ended with the now famous quote

“Since your most serene majesty and your high mightinesses require from me a clear, simple, and precise answer, I will give you one, and it is this: I cannot submit my faith either to the pope or to the councils, because it is clear as the day that they have frequently erred and contradicted each other. Unless therefore I am convinced by the testimony of Scripture or by the clearest reasoning, unless I am persuaded by means of the passages I have quoted, and unless they thus render my conscience bound by the word of God, I cannot and I will not retract, for it is unsafe for a Christian to speak against his conscience. Here I stand, I can do no other; may God help me. Amen.”

You can download it free at  Listeners Bible. I recommend the higher quality which has sections.  The total length is 24 minutes.