Crime and Punishment by Fyodor Dostoyevsky, Part 4, chapter 4

I thought this chapter was a powerful fictional portrayal of despair, hopelessness and existentialism. Some quotes from the discussion between Raskolnikov and Sonia:

"And how she cried to-day! Her mind is unhinged, haven't you noticed it? At one minute she is worrying like a child that everything should be right to-morrow, the lunch and all that.... Then she is wringing her hands, spitting blood, weeping, and all at once she will begin knocking her head against the wall, in despair. Then she will be comforted again. She builds all her hopes on you;" [Sonia talking about her adoptive mother, Katerina Ivanova, whom she is supporting by prostituting herself]

But you are a great sinner, that's true," he added almost solemnly, "and your worst sin is that you have destroyed and betrayed yourself for nothing. Isn't that fearful? Isn't it fearful that you are living in this filth which you loathe so, and at the same time you know yourself (you've only to open your eyes) that you are not helping anyone by it, not saving anyone from anything? Tell me," he went on almost in a frenzy, "how this shame and degradation can exist in you side by side with other, opposite, holy feelings? It would be better, a thousand times better and wiser to leap into the water and end it all!" 

"There are three ways before her," he thought, "the canal, the madhouse, or... at last to sink into depravity which obscures the mind and turns the heart to stone." [Remember this when you see suicide, madness and depravity]

"So you pray to God a great deal, Sonia?" he asked her.
Sonia did not speak; he stood beside her waiting for an answer.
"What should I be without God?" she whispered rapidly, forcibly, glancing at him with suddenly flashing eyes, and squeezing his hand.
"Ah, so that is it!" he thought.
"And what does God do for you?" he asked, probing her further.
Sonia was silent a long while, as though she could not answer. Her weak chest kept heaving with emotion.
"Be silent! Don't ask! You don't deserve!" she cried suddenly, looking sternly and wrathfully at him.
"That's it, that's it," he repeated to himself.
"He does everything," she whispered quickly, looking down again.
"That's the way out! That's the explanation," he decided, scrutinising her with eager curiosity, with a new, strange, almost morbid feeling. He gazed at that pale, thin, irregular, angular little face, those soft blue eyes, which could flash with such fire, such stern energy, that little body still shaking with indignation and anger—and it all seemed to him more and more strange, almost impossible. "She is a religious maniac!" he repeated to himself. [Spoiler... By the end of the book Sonia becomes his wife and they live together in happiness and he starts to believe again. The role of God is not to save people in this world, but Raskolnikov is so small minded he hurts Sonia's feelings by saying what he says and takes the guise of a cruel atheist just to be mean because he feels evil in himself and wants to hurt others]