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

And now thy two sons, who were born unto thee in the land of Egypt before I came unto thee into Egypt, are mine; Ephraim and Manasseh, even as Reuben and Simeon, shall be mine.

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 unto him. And Israel stretched out his right hand, and laid it upon Ephraim’s head, who was the younger, and his left hand upon Manasseh’s head, guiding his hands wittingly; for Manasseh was the first-born.

And Joseph said unto his father, Not so, my father; for this is the first-born; put thy right hand upon his head. And his father refused, and said, I know it, my son, I know it; he also shall become a people, and he also shall be great: howbeit his younger brother shall be greater than he, and his seed shall become a multitude of nations. And he blessed them that day, saying, In thee will Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh.