“Joseph saw that his father was placing his right hand upon the head of Ephraim, and it displeased him; he supported his father’s hand, to remove it from the head of Ephraim to the head of Manasseh” (Genesis 48:17). “Joseph saw that his father was placing…” – Rabbi Berekhya said: The hand that overcame one-third of the world,16See Bereshit Rabba 68:12. you are seeking to move it? “Joseph said to his father: Not so, my father, as this is the firstborn; place your right hand upon his head.
His father refused, and said: I know, my son, I know; he too will become a people, and he too will be great; however, his younger brother will be greater than he, and his descendants will be the plenitude of nations” (Genesis 48:18–19). “Joseph said to his father: Not so, my father.… His father refused, and said: I know, my son, I know” – I know the incident of Reuben and Bilha and the incident of Judah and Tamar;17I know that they all acted with pure intentions (Yefe To’ar). if matters that were not revealed to you were revealed to me, matters that were revealed to you, all the more so.
“He too will become a people, and he too will be great” – is it possible that it will be so?18The continuation of the verse states that Ephraim would be “the plenitude of nations.” The midrash asks: Is it possible that one tribe would be so numerous? Rather, this is Joshua, who stopped the orb of the sun and the moon, which have dominion from one end of the world to the other end. Rabbi Yitzḥak said: Bad slave, are you not the purchase of my father…19Joshua said to the sun: ‘You prostrated yourself to my father Joseph in his dream; therefore you must obey me’ (see Bereshit Rabba 84:11).