According to Torah law, when do daughters receive a share of an inheritance from their parents?
Most of the Torah’s laws of inheritance are stated after the daughters of Tzelafḥad object to the possibility that their family will lose out on its inheritance in the land of Israel simply because they had no brothers. In Sefer Bamidbar (27:6-11) the Torah teaches that their argument was accepted and that although sons usually received their father’s inheritance – the expectation being that they would take care of their sisters until their marriage – in the absence of sons, the inheritance would go to the daughters.
All that is true regarding an inheritance from the father. The Mishna (108a) teaches that this is true of a mother’s estate as well. Our Gemara searches for a source for the fact that a son inherits his mother, and concludes that it is learned from the fact that a daughter inherits her mother. One of the pesukim that describes the laws derived from the story of the daughters of Tzelafḥad (Bamidbar 36:8) teaches that “any daughter inheriting from the tribes of Israel,” which is understood to include a situation where mother and father are from separate tribes. Having determined that a daughter inherits from her mother, the Gemara suggests a kal va-ḥomer – an a fortiori argument – as follows. If a daughter, who has less rights of inheritance from her father’s estate, nevertheless inherits her mother, certainly a son, who has stronger rights in inheriting his father’s estate, will inherit from his mother.
Following this argument, the Gemara continues and concludes that since both sons and daughters inherit their mothers, the sons have priority in this case just as they do in cases when their father passes away. This position is rejected by Rabbi Zekharya ben HaKatzav who believes that sons and daughters should share equally in the mother’s estate, because of the concept of dayo. The rule of dayo la-ba min ha-din le-hiyot ka-nidon limits what we learn from a kal va-ḥomer to the original teaching, so that the newly derived law cannot have greater impact than the original source.
The Gemara relates that several amora’im wanted to accept Rabbi Zekharya ben HaKatzav’s ruling, and the Talmud Yerushalmi reports that the Babylonian Sages had a tradition that followed his teaching. Nevertheless, the halakha follows the other opinion, and boys receive preference in inheritance laws also in the case of a mother’s estate.