What are some ways that Elie Wiesel and the other Jews at the camps try to observe their religion in the story the night?

Ellie and the other Jews initially, attempt to observe their faith in secrecy, "Evenings, as we lay on our cots, we sometimes tried to sing a few Hasidic melodies. Akiba Drumer would break out hearts with his deep grave, voice." Later, many chose to fast for Yom Kippur, even though they were starving.