Genesis 48:17-20

48:17 When Joseph saw that his father placed his right hand on Ephraim’s head, it displeased him. So he took his father’s hand to move it from Ephraim’s head to Manasseh’s head. 48:18 Joseph said to his father, “Not so, my father, for this is the firstborn. Put your right hand on his head.”

48:19 But his father refused and said, “I know, my son, I know. He too will become a nation and he too will become great. In spite of this, his younger brother will be even greater and his descendants will become a multitude of nations.” 48:20 So he blessed them that day, saying,

“By you will Israel bless, saying,

‘May God make you like Ephraim and Manasseh.’”

So he put Ephraim before Manasseh.