SNM:
It's a quote originally attributed to Genghis Khan, and which was later used in the Conan movie adaptation.
I don't think Conan ever actually said it in the original Robert E. Howard stories though.
So Genghis Khan thought along the same lines as the bloke who Richard Dawkins described as:
"Arguably the most unpleasant character in all fiction: jealous and proud of it; a petty, unjust, unforgiving control-freak; a vindictive, bloodthirsty ethnic cleanser; a misogynistic, homophobic, racist, infanticidal, genocidal, filicidal, pestilential, megalomaniacal, sadomasochistic, capriciously malevolent bully."
Guess who?