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Many of us bless our children on Friday nights. The bracha for daughters is pretty easy to understand- among other things we wish them to be as great as Sarah, Rivka and Leah- towering female figures in the Torah, about whom much is known through a pshat reading of Bereshit. The corresponding figures for a son, though, are Ephraim and Menashe. Besides having been born to Yosef and Potiphar's daughter and their deathbed "adoption" by Yaakov, we know almost nothing about them. What are some good sources for their being of such a stature that we would want our sons to emulate them?