Q Why do we Bless Girls with Sarah Rivkah Rachel and Leah
What's the common denominator with Ephraim and M'nasheh? - IOW what's the "tzu-shtell"?
A. Just like Ephraim and M'nasheh grew up in a "galut environment" in Mitzrayim, so too did the imahos grow up in the homes of Nachor, B'tuel, Lavan, etc. - and yet they all did not fall prey to their environments. Rather they remained Tzaddikim and Tzadkaniyot.