Quotation from: The Chessmen of Mars

Written by: Edgar Rice Burroughs

"And to like to fight they must know how to fight," he said, "for
no man likes to do the thing that he does not know how to do
well."

"Or that some other man can do better than he."

"And so always there will be wars and men will fight," he
concluded, "for always the men with hot blood in their veins will
practice the art of war."