From what place were the heavens created? From the light of the garment of the Holy One, blessed be He, with which He is clothed. He took from it and spread it out like a cloak, and it kept stretching and going until He said to it: Enough. For this reason His name is called Shaddai, for He said to the heavens "Enough" (dai) and they stood firm. And from where do we know that they were created from the light of His garment? As it is said (Psalms 104:2): "He wraps Himself in light like a garment, He stretches out the heavens like a curtain."
God's Garment Of Light
Pirkei DeRabbi Eliezer 3
שָׁמַיִם מֵאֵיזֶה מָקוֹם נִבְרְאוּ? מֵאוֹר לְבוּשׁוֹ שֶׁל הַקָּדוֹשׁ בָּרוּךְ הוּא שֶׁהוּא לָבוּשׁ. לָקַח מִמֶּנּוּ וּפָרַשׂ כַּשַּׂלְמָה וְהָיוּ מוֹתְחִין וְהוֹלְכִין עַד שֶׁאָמַר לָהֶם: דַּי, וְעַל כֵּן נִקְרָא שְׁמוֹ שַׁדַּי, שֶׁאָמַר לַשָּׁמַיִם דַּי וְעָמְדוּ. וּמִנַּיִן שֶׁמֵּאוֹר לְבוּשׁוֹ נִבְרָא? שֶׁנֶּאֱמַר (תהלים קד, ב): ״עֹטֶה אוֹר כַּשַּׂלְמָה נוֹטֶה שָׁמַיִם כַּיְרִיעָה״.