In thee shall Israel bless— i.e.. So eminent and prosperous shall these two tribes be, that it shall become a proverbial form among my posterity, in wishing happiness to others: God make thee as Ephraim and Manasseh; a form, we are told, which continues among the Jews to this day; while their blessing to their female children is, God make thee at Sarah and Rebecca. Zedekiah and Ahab are, on the other hand, proposed for execration. See Jeremiah 29:22.
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.