Final answer:
The eight simple words that caused Elie Wiesel's separation from his mother and sister are not in the provided text but come from the Holocaust narrative 'Night', where simple commands by the Nazis at Auschwitz led to family separations.
Step-by-step explanation:
The eight simple words that caused Elie Wiesel to never see his mother or sister again are not explicitly mentioned in the provided text excerpts. These words are believed to originate from Elie Wiesel's autobiographical account Night, in which he describes his experience during the Holocaust. The separation typically occurred upon arrival at the Auschwitz concentration camp, where families were often torn apart during the selection process with simple directions given by Nazi officers such as "Men to the left! Women to the right!" These simple words directed men and women, boys and girls, to separate lines, which often led to the immediate separation of family members without the chance of saying goodbye.