Final answer:
Raul Hilberg's quote highlights that the genocidal policies of the Nazis during the Holocaust were the culmination of a long history of European anti-Semitism, not a new development. It underlines the importance of understanding the progression of harmful ideologies.
Step-by-step explanation:
Raul Hilberg's quote, "The Nazis did not discard the past, they built on it. They did not begin a development, they completed it." refers to the continuity of anti-Semitic sentiment and discriminatory practices against Jews that culminated in Holocaust.
By indicating that the Nazis 'completed' a development, Hilberg underlines that the roots of Nazi ideology and their genocidal policies were not novel but rather the fruition of a long-standing history of European anti-Semitism. The Nazis built upon this with fervent race-based hatred and pseudo-scientific convictions about Aryan supremacy to justify their actions during the Holocaust.
His quote is vital to remember as it emphasizes the importance of recognizing warning signs in history, the progression of harmful ideologies, and the responsibility society holds to thwart such developments before they culminate in tragedy.