Genesis 48:17-20

17When Joseph saw that his father laid his right hand on the head of Ephraim, it displeased him, and he took his father's hand to move it from Ephraim's head to Manasseh's head.

18And Joseph said to his father, "Not this way, my father; since this one is the firstborn, put your right hand on his head."

19But 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."

20So 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.