How do Elie's thoughts show that he is losing faith in God?

This happens gradually through the novel

-When the people are being lined up in front of the furnace he asks God how he could let this happen.

-In the camp an elder speaks about loosing faith and Eli wonders if God is even his "enemy"

-When angel faced Pipel is hanged in the gallows, Eli wonders where God is? Here Eli hears a voice in his head saying that God is also in the gallows.

In the end I don't think Eli forsakes his faith more than re-evaluates what he had been taught as a child juxtaposed to the Jewish holocaust experience.