במדבר, פרק כ״ז, פסוק י׳

When an individual passes away without leaving any descendants, the chain of inheritance must reverse its usual downward flow and travel back up the family tree. The immediate step directs the estate to the deceased's siblings. Though traditionally framed around brothers, this represents the broader bond of siblings, encompassing sisters as well. Consequently, if there are no male siblings, the sisters hold the right to inherit before the estate moves further away to the uncles [תורה תמימה].

Although the progression of inheritance appears to jump directly from siblings to the uncles, there is a crucial, unmentioned link in this chain: the father of the deceased. If the father is still alive, the estate transfers to him, giving him priority over his own brothers [תורה תמימה, ברכת אשר]. In cases where the father is no longer living, the estate passes to the father's brothers. However, this transfer is not direct. The inheritance first travels back up to the grandfather. From him, it is then passed down to his sons, who are the uncles of the deceased [רלב״ג].

The strict focus on the father's relatives highlights a fundamental principle of biblical inheritance: only the paternal line is legally recognized as the family unit. Relatives on the mother's side do not factor into this legal definition. As a result of this rule, brothers who share the same father will inherit from one another, even if they were born to different mothers [תורה תמימה].