בראשית, פרק מ״ח, פסוק ו׳

After elevating Ephraim and Manasseh to the status of full tribes, equal in rank to his own sons, Jacob sets the boundaries of his blessing. He outlines exactly how Joseph’s extended family will integrate into the future inheritance of Israel.

Jacob addresses the status of any other children Joseph might have. A difficulty arises because Jacob refers to these children as if they are already born, even though there is no prior record of Joseph having additional sons. The primary approach among commentators is that Jacob is speaking conditionally about the future. He wants to make it absolutely clear that if Joseph marries again and has more sons, they will not be granted the status of independent tribes [גור אריה]. Conversely, some scholars suggest that Joseph actually did have more sons or grandsons born after the years of famine [רשב״ם, ספורנו, הטור הארוך, רלב״ג, שטיינזלץ]. These children are left unnamed either because they were simply too young at the time of Jacob's blessing, or because they eventually died without leaving heirs. Another perspective offers a more tragic reason for their absence: unlike Ephraim and Manasseh, who maintained their distinct identity, these later children assimilated entirely into Egyptian culture and ceased to be a part of Israel [קונטרס חיבה יתירה].

Jacob establishes that any additional descendants will remain strictly under Joseph's line, rather than being adopted as Jacob's own. They will not form their own tribes. This raises a deeper question as to why Joseph himself is not counted as one massive, unified tribe. [אור החיים] explains that Joseph actually attained the rank of a patriarch, placing him on the same level as Jacob himself. Because of this elevated status, he cannot be counted in the same tier as the individual tribes.

Instead of receiving their own distinct territories, any further children of Joseph are to be absorbed into the families of Ephraim and Manasseh. They will receive their land portions as smaller family units within those two established tribal borders. Interestingly, even though Ephraim and Manasseh function as two distinct tribes, they are still treated together as a single united tribe for certain communal matters in Jewish law [תורה תמימה].

This division of land sparks a fundamental debate regarding the true nature of Joseph’s birthright. According to [רש״י], the land of Israel was divided equally based on the total population of the nation, meaning every individual received the exact same amount of property. In this view, the elevation of Ephraim and Manasseh did not grant Joseph more physical land than anyone else. Rather, his birthright was a matter of immense honor and authority, giving his family the prestige of being recognized as two separate tribes with their own leaders, flags, and borders. [רמב״ן] strongly disagrees, arguing that a birthright based merely on honor strips Joseph of the essential right to a double portion of actual property. He maintains that the land was divided into twelve equal sections based on the number of tribes, regardless of population size. By establishing Ephraim and Manasseh as two distinct tribes, Jacob practically granted Joseph two full, equal territories in the land of Israel, thereby fulfilling his birthright in a tangible, material way.