וַיִּקְרָ֥א יוֹסֵ֛ף אֶת־שֵׁ֥ם הַבְּכ֖וֹר מְנַשֶּׁ֑ה כִּֽי־נַשַּׁ֤נִי אֱלֹהִים֙ אֶת־כׇּל־עֲמָלִ֔י וְאֵ֖ת כׇּל־בֵּ֥ית אָבִֽי׃
And Yosef called the name of the first-born Menasheh: “For God hath made me forget all my toil, and all my father’s house.”
Exact Source: Bereishis Rabbah 86:5
רַבָּנָן אָמְרֵי: וַיַּרְא אֲדֹנָיו כִּי ה׳ אִתּוֹ — וּבַסּוֹף שָׁכַח, דִּכְתִיב: כִּי נַשַּׁנִי אֱלֹהִים אֶת כָּל עֲמָלִי.
English of Source Text: The Midrash observes that although Yosef had been blessed with the Divine presence, the verse later says that he forgot all his toil. The passage connects the wording of 41:51 with Yosef's forgetting.
On the passuk: This is the classical midrashic source directly connected with Yosef's naming of Menasheh.
Type of Learning: Derash on the verse (classic midrash) — not a formal named middah of the 13.
What Is Learned: The verse’s “all my toil” is read as referring to Yosef’s forgetting Torah learning under the pressure of his experience in Egypt.