Family tensions and struggles over inheritance tear Gilead's household apart when his sons unite against their brother Jephthah, who was born from a different relationship. Gilead had a legal wife to whom he was properly married. When the sons of this legal wife grow up, they turn against Jephthah. In addressing him, they refer to his mother as a different woman, viewing her as a foreign and inferior figure [ביאור שטיינזלץ]. They choose this delicate phrasing carefully to protect their father's honor, deliberately avoiding calling Jephthah's mother a prostitute [מצודת דוד].
The brothers physically and violently force Jephthah out of their home [מצודת דוד, ביאור שטיינזלץ], declaring that he will receive no share in their father's estate. They base their claim on a specific inheritance rule. According to Jewish law, the children of a legal wife inherit the money from their mother's marriage contract. Because Jephthah is the son of a concubine, who typically does not have such a contract, he has no right to this specific portion of the inheritance. The brothers use this technicality as their excuse to drive him away [אהבת יהונתן].
Despite the brothers' claims, commentators stress that expelling Jephthah and denying his inheritance is a complete injustice. By law, the son of a concubine is still fully entitled to a share of the general estate alongside the other sons [מלבי״ם]. More importantly, Jephthah actually holds the legal rights of the firstborn son, a status that cannot be revoked under any circumstances [אהבת יהונתן]. Ultimately, forcing Jephthah out of the city is not a valid legal action, but rather an act of robbery and violence [מלבי״ם].