which sends couriers by sea, in papyrus vessels on the waters. Go, swift messengers, to a people tall and smooth-skinned, to a people widely feared, to a powerful nation of strange speech, whose land is divided by rivers.
2. Sending ambassadors by the sea. This relates strictly to the state of those times. It would appear that this nation solicited the Egyptians or Syrians to harass the Jews, or that the Assyrians employed them for the purpose of harassing the Jews, or that they had formed an alliance with the Egyptians, in order that, by their united force, they might prevent the power...
Interpreters are very much at a loss where to find this land that lies beyond the rivers of Cush. Some take it to be Egypt, a maritime country, and full of rivers, and which courted Israel to depend upon them, but proved broken reeds; but against this it is strongly objected that the next chapter is distinguished from this by the title of the burden of Egypt.
Commenting on Isaiah 18:1-7
That sendeth ambassadors by the sea,.... The Red Sea, which washed the coasts of Egypt and Ethiopia, and which were united into one kingdom under Sabacus, or So the Ethiopian, called king of Egypt, Kg2 17:4 and this kingdom, or rather the king of it, is here described as sending ambassadors by sea to foreign courts, to make leagues and alliances, and thereby strengthen himself...