"And the LORD spoke to Moses, Go down" (Exodus 32:7). The Holy One, blessed be He, said to Moses: Go down from your greatness. Did I give you greatness for any reason except for Israel's sake? Now that Israel have sinned, what need have you of your greatness? Immediately Moses' strength weakened. As soon as He said to him, "Let Me alone, that I may destroy them," at once Moses said: This matter depends on me. Immediately he stood and gathered strength in prayer. A parable: to a man who grew angry at his son and was striking him a great blow, while his friend sat before him and was afraid to say a word. He said: were it not for this friend of mine who sits before me, I would have killed you. He said: since the matter depends on me, I will stand and save him. Immediately he stood and saved him.
Go Down From Your Greatness and Moses Found Strength in Prayer
Yalkut Shimoni on Torah 391:15
וַיְדַבֵּר ה' אֶל מֹשֶׁה לֶךְ רֵד. אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא לְמֹשֶׁה. לֵךְ מִגְּדֻלָּתְךָ, כְּלוּם נָתַתִּי לְךָ גְּדֻלָּה, אֶלָּא בִּשְׁבִיל יִשְׂרָאֵל, עַכְשָׁיו שֶׁיִּשְׂרָאֵל חָטְאוּ, גְּדֻלָּתְךָ לָמָּה לְךָ. מִיַּד תָּשַׁשׁ כֹּחוֹ שֶׁל מֹשֶׁה. כֵּיוַן שֶׁאָמַר לוֹ "הֶרֶף מִמֶּנִּי וְאַשְׁמִידֵם", מִיַּד אָמַר מֹשֶׁה, זֶה הַדָּבָר תָּלוּי בִּי, מִיַּד עָמַד וְנִתְחַזֵּק בִּתְפִלָּה. מָשָׁל לְאָדָם שֶׁכָּעַס עַל בְּנוֹ, וְהָיָה מַכֵּהוּ מַכָּה גְדוֹלָה, וְהָיָה אוֹהֲבוֹ יוֹשֵב לְפָנָיו, וּמִתְיָרֵא לוֹמַר דָּבָר, אָמַר, אִלְמָלֵא אוֹהֲבִי זֶה שֶׁיּוֹשֵב לְפָנַי, הֲרַגְתִּיךָ, אָמַר, הוֹאִיל וְהַדָּבָר תָּלוּי בִּי אֶעֱמֹד וְאַצִּילוֹ, מִיָּד עָמַד וְהִצִּילוֹ.