וְעַתָּ֡ה שְׁנֵֽי־בָנֶיךָ֩ הַנּוֹלָדִ֨ים לְךָ֜ בְּאֶ֣רֶץ מִצְרַ֗יִם עַד־בֹּאִ֥י אֵלֶ֛יךָ מִצְרַ֖יְמָה לִי־הֵ֑ם אֶפְרַ֙יִם֙ וּמְנַשֶּׁ֔ה כִּרְאוּבֵ֥ן וְשִׁמְע֖וֹן יִֽהְיוּ־לִֽי׃
And now thy two sons, who were born unto thee in the land of Egypt before I came unto thee into Egypt, are mine; Ephraim and Manasseh, even as Reuben and Simeon, shall be mine.
Read kabbalistic (mystical) interpretation of Genesis 48:5: and classical mystical sources.