Answer: liberty and justice for all <--- the answer
“All humans are descended from Adam and Eve,” said Muhammad in his last known public speech. “There is no superiority of an Arab over a non-Arab, or of a non-Arab over an Arab, and no superiority of a white person over a black person or of a black person over a white person, except on the basis of personal piety and righteousness.”
Go back to the text and re-read a passage where Watson made a discovery. If Sherlock praises him, you've got your answer. I'm sorry if this wasn't much help, but I don't have any text to go off of.
