Confronting the tragedy of a man who dies without children, the Torah provides the Commandment of Levirate marriage as a mechanism to ensure his continuity in the world. By marrying the widow, the surviving brother acts to preserve the deceased's legacy, though the exact nature of this preservation creates a fascinating tension between the simple reading of the biblical narrative and the established legal tradition.
Some commentators maintain a literal interpretation, suggesting that the firstborn son born to the widow and her brother-in-law must be given the exact name of the deceased [אבן עזרא, רשב״ם, שד״ל]. If the deceased was named Reuben, the newborn would also be named Reuben, and this child would eventually inherit the dead man's estate. However, many scholars firmly reject this literal approach due to grammatical and historical difficulties [רמב״ן, מלבי״ם, הכתב והקבלה, רש״ר הירש, בכור שור, ביאור יש״ר]. Historically, when Boaz married Ruth to establish a legacy for her deceased husband Machlon, their child was named Oved, not Machlon. Instead, establishing the deceased's name means that the child is conceptually and familiarly recognized as his continuation, while the surviving brother steps directly into the legal shoes of the departed.
Because of these complexities, the Talmudic and legal tradition departs entirely from the literal reading, assigning precise legal definitions to the process [רש״י, מזרחי, תורה תמימה, גור אריה, ריב״א]. In this framework, the primary obligation to perform this Commandment does not center on a future baby, but rather falls upon the eldest surviving brother. By fulfilling this duty, this older brother assumes the legal status of a firstborn regarding inheritance, entitling him to a double portion of their father's assets. Furthermore, the Commandment applies exclusively to a widow capable of having children, inherently excluding a naturally sterile woman. The preservation of the deceased's name is understood here as a financial directive: the surviving brother inherits the deceased's share of the family estate.
The ultimate goal of this Commandment is biological and historical continuity, ensuring that a person's memory is not erased. The total erasure of a Jewish name is considered the most severe curse, and Levirate marriage is designed specifically to prevent this profound tragedy [ברכת אשר]. Consequently, a man who is physically incapable of fathering children is excluded from this law, as his biological lineage is already considered concluded. To address the dual focus on preserving the deceased's memory, some explain that Levirate marriage operates simultaneously on two distinct planes [מלבי״ם, הכתב והקבלה]. On the material level, the surviving brother preserves the legacy through the inheritance of the estate. On the biological level, the widow brings forth offspring that ensure the family's physical continuation.
On a much deeper, mystical level, the resulting child is far more than a legal heir or a carrier of a family name [רבנו בחיי, הכתב והקבלה, ספורנו]. Before God, this child is considered the actual offspring of the deceased, born from the spiritual power of the original marriage. According to Kabbalistic tradition and the secret of reincarnation, the soul of the departed brother is transplanted and brought to completion within the body of the new baby. This profound spiritual reality explains historical biblical events, such as Onan's refusal to father a child for his deceased brother Er; Onan understood that the child would not truly be his own, but rather a vessel for his brother's soul. Ultimately, the Torah demands profound self-sacrifice and pure intentions from the surviving brother. He is called to act not for his own legacy, but with complete devotion to resurrecting the name, estate, and soul of his fallen brother.