Genesis 48:19-20

19But his father refused and said, “I know, my son, I know. He too will become a people, and he too will become great. Nevertheless, his younger brother will be greater than he, and his descendants will become a group of nations.” 20He blessed them that day and said, “In your name will Israel pronounce this blessing: ‘May God make you like Ephraim and Manasseh.’ ” So he put Ephraim ahead of Manasseh.