John Wesley on Isaiah 7:18

The fly - The flies. So he calls these enemies, to imply their great numbers. In - In their extremity, where they go out into the sea. Rivers - Of the river Nile, which may be called rivers, either for its greatness, or because towards the end of it, it is divided into seven streams. When the Chaldeans had in good measure subdued the Egyptians, it is probable great numbers of the Egyptian soldiers listed themselves in the Chaldean army, and with them invaded the land of Judah. The bee - The Assyrian army, compared to bees, as for their numerous forces and orderly march, so for their fierce attempts and mischievous effects. Assyria - In the empire of Assyria, or Babylon; for these two were united into one empire, and therefore in scripture are promiscuously called sometimes by one title, and sometimes by the other.