The quote you are after is one of the key quotes in Night that directly relates to the theme of God and religion in the context of the holocaust. It comes as the prisoners watch a child, beloved of all the camp, being hung. His death is not swift, but is long and agonising. Although many of the prisoners do not cry, having suffered too much, witnessing this event they do cry.
"Where is God? Where is He?” someone behind me asked. ..
For more than half an hour [the child in the noose] stayed there, struggling between life and death, dying in slow agony under our eyes. And we had to look him full in the face. He was still alive when I passed in front of him. His tongue was still red, his eyes were not yet glazed.
Behind me, I heard the same man asking:
“Where is God now?”
And I heard a voice within me answer him:
“Where is He? Here He is—He is hanging here on this gallows. . . .”
This gruesome event clearly indicates the nadir of the relationship that Eliezer has with God. The death of the child could also be said to symbolise the death of Elie's childhood and innocence. Interestingly, before the holocaust, questioning God was obviously something that had never entered Elie's mind. He said to Moshe in response to the question why he prays, “Why did I pray? What a strange question. Why did I live? Why did I breathe?” His experiences of the holocaust clearly challenge and impact his belief about God. One way of looking at this novel is to think of it as a kind of coming of age story, but one in which the innocence and youth of the protagonist are gradually flayed away by the horror he undergoes.
During one of the preliminary “ceremonies” for a hanging, Juliek whispers to Eliezer, “This ceremony, will it be over soon? I am hungry…” This suggests that the prisoners cared more about their hunger than the death of one of their neighbors.