And he blessed them that day, saying, In thee shall Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh. In thee shall Israel bless - That is, in future generations the Israelites shall take their form of wishing prosperity to any nation or family from the circumstance of the good which it shall be known that God has done to Ephraim and Manasseh: May God make thee as fruitful as Ephraim, and multiply thee as Manasseh! So, to their daughters when married, the Jewish women are accustomed to say, God make thee as Sarah and Rebekah! The forms are still in use.
Related Commentaries of Genesis 48:20
Genesis 48:20
20 And he blessed them that day, saying, In thee shall Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh.