Jamieson, Fausset and Brown on Isaiah 19:4

4. cruel lord--"Sargon," in Hebrew it is lords; but plural is often used to express greatness, where, one alone is meant (Ge 39:2). The parallel word "king" (singular) proves it. Newton makes the general reference to be to Nebuchadnezzar, and a particular reference to Cambyses, son of Cyrus (who killed the Egyptian god, Apis), and Ochus, Persian conquerors of Egypt, noted for their "fierce cruelty." Gesenius refers it to Psammetichus, who had brought into Egypt Greek and other foreign mercenaries to subdue the other eleven princes of the dodecarchy.