Isaiah 47:8 - Ellicott's Commentary On The Whole Bible

I am, and none else beside me... — The boasts of Babylon are purposely embodied by the prophet in praises that recall Jehovah’s assertion of His own eternity. She practically deified herself. So a like boast is put into the mouth of Nineveh in Zephaniah 2:15, and was repeated almost verbally by the poets of Rome: Terrarum dea gentiumque Roma, cui par est nihil, et nihil secundum (Martial).