Comentario sobre Génesis 48:4

ונתתיך לקהל עמים AND I WILL MAKE OF THEE AN ASSEMBLY OF PEOPLES — He announced to me that there were yet to issue from me an assembly of peoples (i.e. at least two more tribes). Now, it is true that He then said to me, (Genesis 35:11) “A nation and an assembly of nations [shall be of thee]”, but when He said “a nation” He intended it to refer to Benjamin who was not yet born, and this promise of “a nation” has been fulfilled by the birth of Benjamin, and for that reason I do not mention it now. “An assembly of nations [shall be of thee]”, however, presupposes that two more would descend from me besides Benjamin. Consequently, since no other son besides Benjamin was born to me, He was really telling me that one of my tribes (i.e. the tribe formed by one of my sons) would be divided so as to constitute at least two tribes, thus giving that son more importance, and that privilege I confer upon you (Genesis Rabbah 82:4; Pesikta Rabbati 3).

ונתתיך לקהל עמים ונתתי את הארץ, at the time Yaakov received this promise all his sons with the exception of Binyamin had already been born, and G’d had already said to me when I left on the way to Charan (in the dream of the ladder) “the land which you lie on I shall give to you and to your descendants.” (28,13) If so, it had been G’d’s intention at that time already to give me a “community of nations, i.e. separate tribes. Seeing that you and your children are my descendants and it is unreasonable to assume that G’d had had only you personally in mind when speaking of קהל עמים, a community of nations, it is clear to me that I have the right to designate both these sons of yours as being part of this concept קהל, i.e. that each of them will become a founding father of one of these tribes which constitute this community of nations.

הנני מפרך והרבך, "I am fructifying and multiplying you, etc." The repetition of these expressions, i.e. both "multiply and fructify," alludes to G'd's promise to Jacob in 35,11 that he would be fruitful and would multiply. At the time he had interpreted that promise to mean that two more sons (at least) would be born to him. In the meantime he had found out that only one more son, i.e. Benjamin was born to him.