The quote that best illustrates the theme of "The Monkey's Paw" is:
“The first man had his three wishes. Yes,” was the reply; “I don’t know what the first two were, but the third was for death. That’s how I got the paw.”
This quote encapsulates the central theme of the story: the dangers of tampering with fate and the consequences of human desires. It suggests that while the monkey's paw can grant wishes, those wishes often come with unforeseen and tragic outcomes, emphasizing the idea that not all wishes should be granted. The reference to the first man's ultimate wish for death serves as a warning about the inherent risks involved in trying to manipulate one's destiny.