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לך לך. לַהֲנָאָתְךָ וּלְטוֹבָתְךָ, שָׁם אֶעֶשְׂךָ לְגוֹי גָדוֹל, כָּאן אִי אַתָּה זוֹכֶה לְבָנִים, וְעוֹד שֶׁאוֹדִיעַ טִבְעֲךָ בָּעוֹלָם: לך לך GET THEE OUT (literally, go for thyself) — for your own benefit, for your own good: there I will make of you a great nation whilst here you will not merit the privilege of having children (Rosh Hashanah 16b). Furthermore, I shall make known your character throughout the world (Midrash Tanchuma, Lech Lecha 3)