CHASSIDIC PEARLS BY RABBI LAZER BRODY PARSHAS VAYECHI

May Hashem help you become like Ephraim and like Menashe (Bereishit 48:20). It is a very beautiful custom for the father to bless his when he returns home from the synagogue on Shabbat. There's a slight difference, however, in how a father blesses his daughters and how he blesses his sons. We bless our daughters that they should become like our matriarchs, namely, "May Hashem help you become like Sarah, Rivka (Rebecca), Rachel, and Leah." Correspondingly, we would expect to bless our sons in the name of our patriarchs, that Hashem help them to become like Avraham (Abraham), Yitzchak (Isaac), and Yaakov (Jacob). Surprisingly, our forefather Yaakov himself ordered all subsequent generations to bless their sons in the following fashion: "May Hashem help you become like Ephraim and like Menashe." Why?