In Galus there are two ‘first borns’:
Yosef’s first born is Menashe: to remember from where you come and not to be influenced by the environment you are in.
Ya’akov’s first born is Ephrayim: to succeed and prosper and take something from the Exile and to ultimately transform it.
Yosef therefore objects to the switching of the hands but Ya’akov insists.
