The word night is a key word in this section of the book. Why is it important?

Though probably somewhat an obvious theme given the title, night is constant theme that appears throughout the book, mostly to symbolize the darkness into which the world has plummeted. The first time that “night” is made apparent is when Wiesel describes the first night in the concentration camp, saying, “never shall I forget that night, the first night in camp, which has turned my life into one long night, seven times cursed and seven times sealed.” An endless night symbolizes how Weisel and his fellow prisoners experienced time, in which routine violence governs their existences, and in which day offers no respite from darkness.