In Chapter 3 of Night, when questioned by the S.S Officer, why did Elie lie about his age and occupation?

In the third section of Night, Elie and his father have just arrived at Auschwitz. They are told by another prisoner that Elie needs to lie about his age. He needs to say he is eighteen and his father needs to say he is forty. This will give them the greatest chance of survival. If the SS officers see that the two men can work, then they will keep them around instead of killing them right away.

Elie tells the guards he is eighteen and a farmer. He thinks that if the officers think he has worked manual labor, then his chances are better. Elie and his father are chosen for work detail and are kept together. Elie is happy that he gets to stay with his father. He thinks he can watch out for him and keep him safe. At this point they still are not sure of where they are or what goes on here. As they start marching they pass a ditch were babies are being burned alive, then pass another ditch where adult bodies are being thrown. The men break down in tears. Elie feels a sense of where they are. He knows that his and his father's lives are in danger.

This is the first time we see Elie start to question his faith. He just doesn't comprehend how God could allow these things to happen. He vows to never forget, and he teaches us, through his terrible tragic nightmare, that we are to never forget as well. If we do forget, it is bound to happen again.