Near the end of his life, Jacob reflects on a divine encounter from years past, using a sacred promise as the foundation to grant a unique status to Joseph and his sons. By revealing how he decoded God's message, Jacob establishes both the spiritual and legal authority to elevate his grandsons, Ephraim and Manasseh, to the rank of independent tribes.
When recounting this divine encounter, Jacob subtly shifts the original language. While God initially spoke of fruitfulness and multiplication as a command, Jacob frames it as a direct promise from God. The primary approach among commentators is that Jacob realized this was not an instruction for him to father more children, but rather a divine gift and blessing, meaning God Himself would ensure the multiplication of his family [כלי יקר, קונטרס חיבה יתירה]. Because Jacob did not have any more sons after Benjamin following that prophecy, he concluded that this promise of growth would be fulfilled through his grandchildren [מלבי״ם].
Following this logic, Jacob explains his understanding of God's promise that he would become an assembly of nations. Since no further sons were born to him, he deduced that one of his existing tribes was destined to split in two, with both halves recognized as fully independent tribes [רש״י, חזקוני, אור החיים]. The specific phrasing used by God precisely indicates that two distinct nations or tribes would emerge from a single source [גור אריה, מזרחי]. Furthermore, this establishes a fundamental principle that even a single tribe can be considered a complete assembly in its own right [תורה תמימה]. The nature of these blessings is distinct: while the promise of becoming a nation refers to political sovereignty and kingship—ultimately realized through the tribe of Benjamin—the blessing of becoming an assembly of nations specifically grants the right to inherit the Land of Israel as separate, distinct groups [העמק דבר].
The divine vision also inextricably links the blessing of descendants to the blessing of the land. Commentators agree that Jacob uses this connection to explain the logic behind granting Joseph a double portion. Because God gave the land to Jacob and promised it to his descendants, the land is conceptually His to distribute as he chooses. Exercising this authority, Jacob grants Joseph the unique gift of tribal division, allowing Ephraim and Manasseh to inherit portions of the land just like Jacob's oldest sons, Reuben and Simeon [רד״ק, ספורנו, שד״ל, בכור שור]. This decisive action effectively transfers the birthright to Joseph, the firstborn of Jacob's primary wife, Rachel [רלב״ג].
By emphasizing that the land is given as an everlasting possession, Jacob delivers a crucial message and warning to Joseph. He reminds him that regardless of the immense power and high status their family currently enjoys in Egypt, their residence there is strictly temporary. Their true and eternal heritage lies solely in the land of Canaan [קונטרס חיבה יתירה].