Conversation so far:
What are the Cross Road Blues lyrics?
Both versions of Cross Road Blues open with the protagonist kneeling at a crossroads to ask God's mercy
What happens after Johnson asks for mercy in Cross Road Blues?
Cross Road Blues has been used to perpetuate the myth of Johnson selling his soul to the Devil for his musical ability.

Question: What does he say in the song to give this idea?
Self-contained rewrite: What does Johnson say in Cross Road Blues to give this idea that he is selling his soul to the Devil for his musical ability?