Genesis 48:18

18 Joseph said to his father, "You are doing it wrong, Father. Manasseh is the firstborn son. Put your right hand on 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 He was the Angel who saved me from all my troubles. Now I pray that he will bless these boys. May my name be known through these boys, and may the names of my ancestors Abraham and Isaac be known through them. May they have many descendants on the earth."

17 When Joseph saw that his father put his right hand on Ephraim's head, he didn't like it. So he took hold of his father's hand, wanting to move it from Ephraim's head to Manasseh's head.

18 Joseph said to his father, "You are doing it wrong, Father. Manasseh is the firstborn son. Put your right hand on his head."

19 But his father refused and said, "I know, my son, I know. Manasseh will be great and have many descendants. But his younger brother will be greater, and his descendants will be enough to make a nation."

20 So Israel blessed them that day and said, "When a blessing is given in Israel, they will say: 'May God make you like Ephraim and Manasseh.'" In this way he made Ephraim greater than Manasseh.