In Malamud's short story, "The Magic Barrel," the author does not present a "thesis." We can, however, discover the story's themes. A thesis is defined as...
...a proposition stated or put forward for consideration, especially one to be discussed and proved...
Malamud does not come right out and tell the reader what to think. But his themes, the life-truths he wishes to share with the reader, can be discovered through observation. The themes are presented in the story in the form of the narrative.
There are several themes in the story. The first deals with one's identity. When Leo goes out walking with Lily Hirschorne, one of Salzman's potential brides, he becomes aware that he is not the man he believed himself to be. His relationship with God does not exist:
..."I think," he said..."that I came to God not because I loved him, but because I did not."
His lack of a relationship with God is devastating to Leo, for his entire future was based upon serving God and a congregation. Leo realizes that he is imperfect. He knows he is living without love in his life. And while he believes that he has lost a great deal, he feels that his "redemption" can be found in love—something he never looked for in his arrangement with Salzman.
Another theme is God and religion, and for Leo, his identity is tied closely to God and his faith, for he "has always been interested in the Law." In finding himself, he may also find a relationship with God.
Central to Malamud’s ‘‘The Magic Barrel’’ is the idea that to love God, one must love man first.
Leo has not learned to love others; he does not love himself. And so, he is unable to love God.
...he did not love God as well as he might, because he had not loved man.
While Leo has attended classes and learned about religion from the theoretical and analytical perspectives, he has never learned to know and live it in a personal way: he has studied the facts, but not practiced love—he has always approached religion (and life, it seems) at arm's length. It would appear that this side of his work (loving others) has never occurred to him before. And while he acts dejected and defeated for a time after realizing his imperfections, he finally decides that he must go out and look for love in the world...not through a marriage arranged by Salzman. Ironically, however, it is through Salzman that Leo finds the picture of Stella—and love. In helping Stella to find redemption, he is learning to love, and traveling much the same road as she is: neither of them is perfect, but each is capable of loving another, and each desires a fresh start. It is no mistake that Leo meets Stella on a spring evening. Spring denotes new life and rebirth.
Malamud conveys to the reader (through his narrative) that to love others is to be truly fulfilled. And to love others allows one to love self, and moreover, love God—which in central to Leo's relationship with God and those he will serve.