Isaiah 19:16-18. “In that day shall Egypt be like unto women: and it shall be afraid and fear because of the shaking of the hand of the Lord of hosts, which He shaketh over it. And the land of Judah shall be a terror unto Egypt, every one that maketh mention thereof shall be afraid in himself, because of the counsel of the Lord of hosts, which He hath determined against it. In that day shall five cities in the land of Egypt speak the language of Canaan, and swear to the Lord of hosts: one shall be called, The city of destruction.”
“In that day” is the immediate fall of Egypt as well as its future fall when Christ returns. Judah will become the instrument of judgment. The attitude of Egypt toward Israel would be changed, even to the extent of five Egyptian cities adopting Hebrew, the language of Israel, as its common tongue. This particular prophecy could be considered to have been fulfilled when Alexander the Great conquered Egypt, and Hellenistic Greek became the common tongue in Canaan and elsewhere and was adopted in Egypt (where the Septuagint Version was produced.
In verse 18, the “city of destruction” or literally Ir-ha-heres, could indicate the destruction of idolatry. That destruction took place after the successive invasions of the Assyrians, Chaldeans, Persians, and Greeks.
In that day also brings us to the coming of the second advent of Christ, when the land of Judah becomes the center of world government and is a terror to those who resist it.