וַאֲנִ֗י זֹ֣את בְּרִיתִ֤י אוֹתָם֙ אָמַ֣ר יְהוָ֔ה רוּחִי֙ אֲשֶׁ֣ר עָלֶ֔יךָ וּדְבָרַ֖י אֲשֶׁר־שַׂ֣מְתִּי בְּפִ֑יךָ לֹֽא־יָמ֡וּשׁוּ מִפִּיךָ֩ וּמִפִּ֨י זַרְעֲךָ֜ וּמִפִּ֨י זֶ֤רַע זַרְעֲךָ֙ אָמַ֣ר יְהוָ֔ה מֵעַתָּ֖ה וְעַד־עוֹלָֽם׃ (ס)
「至於我，我與他們所立的約乃是這樣，」永恆者說：「我加在你身上的靈，和我放在你口中的話，必不離開你的口，也不離開你後裔的口，也不離開你後裔之後裔的口，從今時直到永遠。」這是永恆者說的。
The Jewish Spiritual Heroes
When he was nearing his end, Rav Joseph wanted assurance that the Torah would remain in his family and he fasted forty days until he saw in a dream the verse “my words which I have placed in thy mouth will not pass from out of thy mouth” (Isaiah 59, 21). Not being satisfied with this he fasted forty more days until he was shown the verse “they shall not pass from thy mouth and from the mouth of thy seed.” When he fasted another hundred days he was shown the verse “they shall not pass from thy mouth and from the mouth of thy seed and from the mouth of the seed of thy seed.” With this he was satisfied, for knowing that his grandchildren would be scholars also, he believed that the Torah would remain in his family.17)בבא מציעא פ״ה א׳.