Raskolnikov backs Lebezyatnikov by confidently identifying Luzhin's motive: a desire to avenge himself on Raskolnikov by defaming Sonya, in hopes of causing a rift with his family. In short, Dostoevsky takes us beyond our limited experience of life and the moral blindness we live in to show us the lives of other people at other times.
She advises Raskolnikov that it was his duty and obligation to undertake the responsibility of his crime and carry the burden until he was redeemed. Raskolnikov was trying to understand how Sonya retained, in spite of her decadence, the virtue of the soul.
Strangely, Raskolnikov begins to feel alarmed at the thought that Porfiry might think he is innocent.
Fearing a search, he hides the stolen items under a building block in an empty yard, noticing in humiliation that he hasn't even checked how much money is in the purse.
His descriptions of the room make us get the distinct impression of the feelings of a person living under such appalling conditions. He wakes to find another complete stranger present, this time a man of aristocratic appearance. Dunya is waiting for him at his room, and he tells her that he will be going to the police to confess to the murders.
Upon entering his room Raskolnikov is deeply shocked to see his mother and sister sitting on the sofa.