Isaiah 43:3 - Ellicott's Commentary On The Whole Bible

I gave Egypt for thy ransom... — Speaking after the manner of men, the prophet paints Jehovah as surrendering Egypt and other kingdoms to the arms of Cyrus, as if they were a price paid to him for liberating the Jews of Babylon. Ethiopia (Heb., Cûsh) may be taken of either the Asiatic or African people that bore that name — Seba as Meroe, between the Blue and White Nile, the modern Dâr Sennâr. Historically, the words find a fulfilment in the conquest of Egypt by Cambyses, who carried into effect his father’s plans. For the thought of the “ransom” comp. Proverbs 11:8; Proverbs 21:18, and the next verse. As a man would sacrifice any number of slaves to ransom a son, so was it in Jehovah’s dealings with His people.