The narrator’s mother, by charging him with watching over Sonny, is asking him to serve as his brother’s keeper. The dynamic between the two brothers echoes, in part, the relationship between the brothers Cain and Abel in the Bible. In that narrative, Cain, after murdering Abel, asks whether he is supposed to be his brother’s keeper. The narrator, following his mother’s death, is presented with a similar dilemma. Since their mother’s death, Sonny’s life has been marred by prison and drug abuse. The tension between the two brothers is so great that after one particular fight, Sonny tells his brother to consider him dead from that point on, a statement that, again, deliberately echoes the biblical narrative of Cain and Abel. Like Cain, the narrator turns his back on his brother and fails, at first, to respond to Sonny when he is prison. He has failed to live up to his mother’s commandment that he watch over his brother—but the failure is only temporary. By the end of the story, the narrator has taken Sonny back into his home. He finally takes on the role of his brother’s keeper, constantly watching and worrying over Sonny as he emerges from the darkness of prison and drug abuse.
The idea of brotherly love extends beyond the relationship between the narrator and Sonny into the community as a whole. Harlem is plagued by drugs, poverty, and frustration, but members of the community come together to watch over and protect one another. The adults spend their Saturday afternoons sharing stories, providing a sense of warmth and protection to the children around them. The narrator, although initially angered by one of Sonny’s old drug-addicted friends, in the end recognizes his connection to the man and offers him money. Even Sonny, for all his problems, helps the people around him endure and survive by channeling their frustrated desires into his music.
Throughout the story, the narrator repeatedly remarks on the barely concealed rage in the people around him as a way of showing both the internal and external conflicts that haunt the characters. Fury and rage are products not only of the limited opportunities that came with being African American at that time but of life in Harlem as well. Early in the story, the narrator notes that his students are “filled with rage.” They are aware of the limited opportunities available to them, and that knowledge breeds an internal, destructive rage that threatens to destroy their lives. With nowhere left to go, they inevitably turn their anger onto themselves, leading them into a life of darkness.
An equally strong rage is present in the streets of Harlem. While looking out the window, Sonny notes with amazement the simple fact that Harlem has not yet exploded. The narrator observes a “furious” man as he drops change into a church bucket. The fury that underlies daily life in Harlem is evident everywhere, even in the religious revivals held on the streets. It’s a fury fueled by desperation and desire, and it finds its truest form of expression in the music Sonny plays at the end of the story. As painful and difficult as that fury is, it also makes the type of jazz Sonny plays possible. It gives life to the religious revival Sonny passes on the street, and although it inevitably exacts an enormous toll on all of the people who bear its weight, it also offers something in return.