What do we learn from "ba'Asher Devar Melech Shilton [u'Mi Yomar Lo Mah Ta'aseh]"?
Refer to 8:5:1:1.
Rav Sadya Gaon: Since the king has authority, no one can challenge him 'what do you do?'
Rashi: "Kol Asher Yachpotz Ya'aseh" (3), because He rules.
Ibn Ezra, Ri Kara (6): Wherever is the king's word, his authority is over you; no one will rebuke him to save you from his hand, for all fear him. This is for mortal kings, and all the more so for the true King, whose honor fills above and below!
Rashbam: Where He is King, He rules and shows His authority 'to do whatever He wants' (3). Shilton is a noun.
Rid: Where the king's command reaches, there is his authority.
Seforno: One might have thought that Hashem does whatever He wants [without reason or purpose] because He has authority, therefore one need not seek reasons for His Mitzvos.
Metzudas David: Since he rules everywhere 1 , no one can protest against him and say to him "Mah Ta'aseh?"
In his kingdom. His Perush on verse 5 proves that he discusses a mortal king. (PF)
Why does it say "u'Mi Yomar Lo Mah Ta'aseh"?
Rashbam: Therefore, people should guard His Mitzvos.
Ri Kara: When He decrees, no one can challenge it.
Rid: No one can oppose his command.
