Why does it say that He does wonders by Himself?
Rashi: Initially, no angel was created when he did these wonders - Shamayim, Eretz, sun and moon.
Radak #1: After mentioning the angels and the Galgalim, which are masters over [the lower beings], it teaches that they are not Kadmon, like He is Kadmon (always existed). Rather, He created them.
Radak #2: Perhaps this refers to what is mentioned after this.
Radak citing Ibn Ezra: This refers to the Heavenly legions.
Radak #3: This refers to forms that are not like bodies; they are purely intellectual. They are above man's understanding; he grasps only physicality 1 . Therefore, they are called Nifla'os. Hashem alone is elevated over them; all other creations are below them. They last forever, therefore it says Ki l'Olam Chasdo; they are Hashem's Chesed on His creations.
Malbim: This refers to wondrous conduct. It is not via an angel or Galgal at all, only via Hashem. He overrides the power of the Elohim and masters, and does wonders with His great strength.
Lev Eliyahu (Shemos p.195): No one else recognizes the wonders. Even the one for whom the miracle is done, does not recognize it (Nidah 31a)!
Radak: The Galgalim and stars are a clear substance; man's eye sees them
