Komentarz do Rodzaju 50:23

על ברכי יוסף [WERE BORN] ON JOSEPH’S KNEES — The meaning is as the Targum gives it: He brought them up upon his knees.

גם בני מכיר, grandchildren. In spite of this, Ephrayim was more fruitful and multiplied more than Menashe as Yaakov had said: “his younger brother will become greater than he.” (48,19)

וירא יוסף לאפרים בני שלשים, “Joseph lived long enough to see three generations of his son Ephrayim.” The true meaning is that whereas Joseph saw three generations from his son Menashe, he saw four generations from his son Ephrayim (Ephrayim plus his great grandson). This is based on the word בני being a possessive of the word שלשים. [However, according to the cantillation, the tipcha under the word בני means it belongs to the word אפרים, Ed.] There is some allusion to this fertility of Ephrayim in Yaakov’s blessing who foresaw greater things for Ephrayim than for Menashe. Concerning the latter Yaakov had said that “he too would develop into a nation,” the implication being that it would take him longer, i.e. more years to do so The word גם in the line גם בני מכיר בן מנשה indicate that Menashe also lived in Joseph’s home; however, seeing that Joseph loved Menashe better than Ephrayim, the Torah mentions the fact that Menashe’s grandchildren were born on Joseph’s knees rather than those of Ephrayim.
The מכיר named here was actually Gilead, son of Machir, son of Menashe. He was the grandfather of Tzelofchod (Numbers 27,1). The Torah wanted to show that Joseph raised righteous people in his own home, people who in turn produced daughters of outstanding caliber such as the daughters of Tzelofchod.