At the beginning of the novel, Wiesel goes into great detail of his religious passion, even at a young age. He believed fervently in his faith, so much so that he wept regularly during prayer and sought someone, anyone, to lead him in his studies of the cabbala.
In section 3 of Night, Elie Wiesel is describing his entry to the concentration camp at Auschwitz. As the Jews are being sorted by gender, age, and ability, they are sent in different directions. Elie and his father are sent in what seems to be the direction of the previously described crematories. As he walks with the herded crowd, they pass open fires where lorries are dumping mounds of bodies. The first fire is burning the bodies of little children, the second one is burning adult bodies. Elie can see the faces of the dead children through the fires. It is at this point that the Jews are of an understanding that they are all about to die and they begin saying the Kaddish, the Jewish prayer for the dead, for themselves. This is when Elie's faith begins to wither away in the flames around him. He says "For the first time, I felt revolt rise up in me. Why should I bless His name?... What had I to thank Him for?" (page 31)
Elie begins to contemplate suicide - an unforgiveable sin - by jumping into the electric barbed wire fences surrounding the camp rather than die slowly in the fires. Just as he is about to bolt to a fence to kill himself, the group is redirected toward a barracks.
On page 32, Wiesel says, "Never shall I forget those flames which consumed my faith forever... Never shall I forget those moments that murdered my God and my soul and turned my dreams to dust." He is implying that from his first moments in a concentration camp, seeing the burning bodies of his fellow Jews and realizing that no one in the world was willing to step forward to stop this total inhumanity, not even God, he began to lose his Jewish faith.