A writer's purpose can usually be found in the themes that he develops in his work. In Elie Wiesel's Night, there are several themes that run throughout the work. 

When Wiesel writes about the cruelty of the Nazi soldiers in  the concentration camps, he is developing the theme of man's inhumanity to man. This becomes poignantly evident when we see changes in Elie himself. At one point he tells the reader that because of his hunger and deprivation, he had become nothing more than "a stomach." 

However, Wiesel also develops a counter-theme of kindness under severe conditions. Despite the suffering and ever-present threat of death, there are still moments when people are kind and giving. At one point, a young violinist named Juliek, who somehow managed to hang on to his violin in the midst of forced marches, plays beautifully for the exhausted and dying prisoners, only to die himself soon after. Elie's father continues to give Elie his own rations as he faces starvation himself. Sometimes prisoners risk their own safety to give comfort to those who are suffering. 

Wiesel's main purpose is no doubt to ensure that the world knows what happened in the camps. His own characters persistently denied their fate early in the book, refusing to believe the things they had heard about the Nazis' plans for them, refusing to believe that such terrible things could happen to them in the twentieth century. Wiesel wants to make sure that the rest of the world doesn't make that mistake.

Elie Wiesel had one main purpose for writing of his experiences during the Holocaust (in his novel Night). According to his introduction, Elie knew that the Holocaust and the period of time which surrounded it "would be judged one day." Given that he recognized this, Elie believed that someone would need to "bear witness." For him, the someone was him. 

Elie did have a fear though: that the testimony he would provide would not be received well. He knew that the only people who would truly understand were those who had lived through and experienced life in the concentration camps. Even though Elie realized that they, readers, would not "know" the reality behind the Holocaust, he hoped that they would "understand." 

This understanding Elie desired was problematic given his language. He worried that he would not be able to help those who did not experience it because the words he chose may be wrong. Regardless of this barrier, Elie stood strong. He refused to stay silent (like the world when it happened--given the first title of his novella: And the World Remained Silent). 

Therefore, his purpose in writing Night was to not stay silent and bear witness to the Holocaust. 

Wiesel's purpose is to give witness to the atrocities of the Holocaust, to speak for the millions who died in the camps. By documenting his experiences, Wiesel hopes to warn future readers about how far hatred and prejudice can go in inflicting death and violence.

Wiesel often said that to remain silent was one of the worst things he could have done after all he lost and all he saw other Jews lose. During his Nobel Peace Prize acceptance speech, Wiesel said, "I have tried to keep memory alive. . . . I have tried to fight those who would forget. Because if we forget, we are guilty; we are accomplices."

That is the main purpose of Night: to make sure that in the future, as living witnesses of the Holocaust die out and the event fades from living memory, that future generations will not forget what happened and that people will endeavor to make sure such atrocities never happen again.

Eli Wiesel tells us in an interview that he wrote Night partly to speak for the dead, and for the survivors who could not speak of the atrocities. He told the story of his survival experience with a sharp honesty that would help those of the future also have an accurate representation.

He witnessed and experienced some of the harshest experiences possible for a child of his age, and although the writing is from the memories of an adult author, the voice is still strikingly innocent. In this way, Wiesel communicates the memories of those who shared his experience.

His observations, descriptions of the struggles of those around him, and description of the actions of Nazi soldiers and guards all work together to document historic events, preserve the memories of himself and those around him, and serve as a warning to future generations about the harsh reality of genocide.

He did not seek to be seen as a hero, or martyr of any sort. Rather, he wrote to preserve the truth, speak for a generation, and give the future something to consider.