In thee, i.e. in thy seed, as appears both from the relative them here, and from Genesis 48:15, where his blessing of them is called the blessing of Joseph; and from the following words, where this is interpreted of Ephraim and Manasseh. And in thee, or in thy seed, i.e. using their names in the form or words of blessing, as eminent examples of blessedness.
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.