Genesis 48:18

18 And he said to his father: It should not be so, my father; for this is the firstborn, put thy right hand upon his head.

Genesis 48:18 Meaning and Commentary

Genesis 48:18

And Joseph said unto his father, not so, my father
It is not right, it should not so be, that the right hand should be put on the youngest, and the left hand on the eldest; for this [is] the firstborn;
directing him to Manasseh, and seeking to guide his hand towards him: put thy right hand upon his head;
Joseph was for proceeding according to the order of birthright, but Jacob was directed by a spirit of prophecy, as follows.

Genesis 48:18 In-Context

16 The angel that delivereth me from all evils, bless these boys: and let my name be called upon them, and the names of my fathers Abraham and Isaac; and may they grow into a multitude upon the earth.

17 And Joseph seeing that his father had put his right hand upon the head of Ephraim, was much displeased: and taking his father’s hand, he tried to lift it from Ephraim’s head, and to remove it to the head of Manasses.

18 And he said to his father: It should not be so, my father; for this is the firstborn, put thy right hand upon his head.

19 But he refusing, said: I know, my son, I know: and this also shall become a people, and shall be multiplied; but his younger brother shall be greater than he; and his seed shall grow into nations.

20 And he blessed them at that time, saying: In thee shall Israel be blessed, and it shall be said: God do to thee as to Ephraim, and as to Manasses. And he set Ephraim before Manasses.