People
I submit to you that if a man hasn’t discovered something that he will die for, he isn’t fit to live.
— Dr. Martin Luther King Jr.

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
This is a challenge about purpose. The speaker argues that a person who hasn't found something worth dying for isn't really fit to live, meaning a life needs a cause big enough to outweigh personal safety. It's a demanding standard about conviction, offered for the listener to weigh.
Context reviewed