“This mass extermination, with all its attendant circumstances, did not, as I know, fail to affect those who took part in it. With very few exceptions, nearly all those detailed to do this monstrous "work," and who, like myself, have given sufficient thought to the matter, have been deeply marked by these events. Many of the men involved approached me as I went my rounds through the extermination buildings, and poured out their anxieties and impressions to me, in the hope that I could allay them. Again and again during these confidential conversations I was asked; is it necessary that we do this? Is it necessary that hundreds of thousands of women and children be destroyed? And I, who in my innermost being had on countless occasions asked myself exactly this question, could only fob them off and attempt to console them by repeating that it was done on Hitler's order. I had to tell them that this extermination of Jews had to be, so that Germany and our posterity might be freed for ever from their relentless adversaries. There was no doubt in the mind of any of us that Hitler's order had to be obeyed regardless, and that it was the duty of the SS to carry it out. Nevertheless we were all tormented by secret doubts.”

Quoted in "Commandant of Auschwitz" (1951)