“וָאֵרָא אֶל אַבְרָהָם אֶל יִצְחָק וְאֶל יַעֲקֹב בְּאֵל שַׁדָּי וּשְׁמִי יְהוָה לֹא נוֹדַעְתִּי לָהֶם.”
“and I appeared to Abraham, Isaac, and Jacob, as God Almighty (אֵל שַׁדָּי), but by My name, YHVH, I did not make Myself known to them.”
The name ‘אֵל שַׁדָּי’ ‘El Shaddai’ is the level of Zeir Anpin.
Moses was on a higher level that the patriarchs. He was at the level of Da’at that is ‘inner’, which means part of the upper three Sefirot.
“לָכֵן אֱמֹר לִבְנֵי יִשְׂרָאֵל אֲנִי יְהוָה וְהוֹצֵאתִי אֶתְכֶם מִתַּחַת סִבְלֹת מִצְרַיִם וְהִצַּלְתִּי אֶתְכֶם מֵעֲבֹדָתָם וְגָאַלְתִּי אֶתְכֶם בִּזְרוֹעַ נְטוּיָה וּבִשְׁפָטִים גְּדֹלִים”
“Say, therefore, to the sons of Israel, ‘I am YHVH, and I will bring you out from under the burdens of the Egyptians, and I will deliver you from their bondage. I will also redeem you with an outstretched arm and with great judgments.”
Rabbi Yehuda says that this verse describes the redemption not in the proper order. It was supposed to say “I will redeem you” then “I will bring you out. He explained that the verse reveals that God wanted to start with the best news, which is going out of Egypt.