the predebate sermon that Luther preached on Matthew 16:13–19. Originally scheduled for the Castle Church, it had to be moved to the university lecture hall because of the number who wished to attend. There, to a packed house, Luther laid out the notion that God would be gracious to all who humbled themselves before him, and that the keys of which Christ spoke were given to all Christians and not simply to the priestly hierarchy. Eck heard the sermon and left the hall with the ominous declaration