" The idea of treating war as anything other than the harshest means of settling questions of very existence is ridiculous,” he challenged the army commanders. “Every war costs blood, and the smell of blood arouses in man all the instincts which have lain within us since the beginning of the world: deeds of violence, the intoxication of murder, and many other things. Everything else is empty babble. A humane war exists only in bloodless brains.” A field marshal who attended the conference reported Hitler warning them “that he would proceed against the Poles after the end of the campaign with relentless vigor. Things would happen which would not be to the taste of the German generals. "

― Richard Rhodes , Masters of Death: The SS-Einsatzgruppen and the Invention of the Holocaust