Isaiah 18:1-3

The land that lies beyond the rivers of Cush was Cush (Nubia), notable for its ships, whose sails looked like the whirring wings of insects over water from a distance. Another view of the whirling wings is that they represent swarming hordes of people, including soldiers. [Note: Young, 1:474-75.] Cush was at the end of the earth in Isaiah’s day and therefore symbolized the ends of the earth; it was a great distance from Judah. Some scholars believe Cush lay within what is now Ethiopia, but others think Cush included modern southern Egypt, Sudan, Eritrea, and northern Ethiopia. [Note: See J. Daniel Hays, "The Cushites: A Black Nation in the Bible," Bibliotheca Sacra 153:612 (October-December 1996):396-409.] Envoys from Cush may have traveled to Moab, Philistia, and Judah seeking an alliance against Assyria. [Note: Oswalt, p. 360.]

Isaiah called on these messengers from Ethiopia to go to a nation tall and smooth (shaven). This was a common description of the Nubians (or Cushites). They were to go to a people feared far and wide, perhaps the Egyptians or the Assyrians. They were to go to a powerful and oppressive nation whose land was divided by rivers, again perhaps the Egyptians, the Assyrians, or even the Medes. Taken together these descriptions represent all great, aggressive nations.

All the recipients of this message, the "inhabitants of the world and dwellers on earth" (Isaiah 18:3), were to hear that a sovereign (the Lord) would issue a call to battle. No one could miss that call when it came.