The note that Madame Khokhlakov gave Alexei, saying that he should visit Katerina Ivanovna at once, “awakened some tormenting feeling in his heart.” Alexei is afraid of Katerina and has been since he first met her. He has only seen her once or twice, maybe three times, and they exchanged few words.
Though Katerina is Dmitri’s fiancée, Alexei doesn’t know her very well and seems to have been trying to avoid her. The torment may come from wondering that she has something bad to tell him—or he is afraid of being attracted to her.
To save time, Alexei passes very close to his father’s house and passes the neighbor’s garden, where his brother Dmitri happens to be. Dmitri invites Alexei to sit down at the table in the gazebo. Dmitri says that he wanted to send Alexei—“an angel”—to both Katerina Ivanovna and to Fyodor on his behalf. He remembers that Katerina sent for Alexei and wrote him a letter, which Alexei shows to his elder brother. Dmitri quickly reads it. He then recites poems to Alexei, commiserating over his depraved condition. He views himself as an “insect” due to his sensuality and says that all of the Karamazovs are like this.
There is a contrast between Dmitri’s lofty image of Alexei as “an angel” and Dmitri’s sense of being a lowly “insect.” He says that all of the Karamazovs are like this, which would necessarily include Alexei. Either Dmitri is mocking his brother’s holiness or admires him genuinely for his wish to be something nobler than what his birth would allow—or both. Dmitri, however, seems to think that he can do nothing to change his nature.