Genesis 48:5, 13-14, 18-20

And now your two sons, who were born to you in the land of Egypt before I came to you in Egypt, are mine; Ephraim and Manasseh shall be mine, as Reuben and Simeon are.

And Joseph took them both, Ephraim in his right hand toward Israel’s left hand, and Manasseh in his left hand toward Israel’s right hand, and brought them near him. And Israel stretched out his right hand and laid it on the head of Ephraim, who was the younger, and his left hand on the head of Manasseh, crossing his hands (for Manasseh was the firstborn).

And Joseph said to his father, “Not this way, my father; since this one is the firstborn, put your right hand on his head.” But his father refused and said, “I know, my son, I know. He also shall become a people, and he also shall be great. Nevertheless, his younger brother shall be greater than he, and his offspring shall become a multitude of nations.” So he blessed them that day, saying, “By you Israel will pronounce blessings, saying, ‘God make you as Ephraim and as Manasseh.’” Thus he put Ephraim before Manasseh.