The expression comes from The Virginian by Owen Wister. It is believed to be the first western novel. Although I'm not sure if it was the first I am sure that it is a good book.
As I mentioned recently in an exchange of notes with Steve Layman of A Layman's Blog, when I was in high school The Virginian was required reading. The Ox-Bow Incident was another western on the list. I doubt if you can find any high school in the United States that would have those two today.
That's a shame because both books had much to teach about life and courage. We had to read others, of course. There were books by Charles Dickens and Henry James and George Orwell as well as a few others I can't recall. I do know that Kon-Tiki also made the list; a choice that baffles me to this day.