Final answer:
The three words that Martin Luther used in his famous refusal to recant his teachings at the Diet of Worms were 'Here I stand.'
Step-by-step explanation:
The three words that Martin Luther used in his famous refusal to recant his teachings at the Diet of Worms were 'Here I stand.' When called upon to recant his beliefs, Luther boldly declared his commitment to his principles and refused to back down. These three words symbolize Luther's unwavering stance and determination to defend his ideas.