"In the summer of 1941, I was called to Berlin to see Himmler. I was given the order to erect extermination camps. I can almost give you Himmler's actual words, which were to the effect: "The Fuhrer has ordered the final solution to the Jewish problem. Those of us in the SS must execute these plans. This is a hard job, but if the act is not carried out at once, instead of us exterminating the Jews, the Jews will exterminate the Germans at a later date.""
January 1, 1970
https://en.wikiquote.org/wiki/Heinrich_Himmler