Read Isaiah 19.
The LORD continued to reveal His prophetic messages for the nations through Isaiah. With Assyria threatening the entire region, it would have been natural to look to neighboring countries for defensive alliances. If all the north will be overrun by the Assyrians, what about Egypt in the south? They, too, will be conquered by the same cruel invaders.
God will use this enemy attack as His instrument. In addition, He will withhold blessings so as to bring about total economic collapse upon Egypt. Why? Because the Egyptians had put their trust in false gods. At its root, the battle is always spiritual. Verse 3 gives some detail. The nation prayed to idols they had made with their own hands out of resources God created and provided. They turned to shysters who claimed to be able to interpret the stars or other omens. Then, there were satanically aligned wizards and conjurers who offered demonic counsel. But when the LORD intervened, they all proved be of no use whatsoever. This was accomplished by Esarhaddon, king of Assyria, in 671 B.C.
The second half of the chapter looks beyond the immediate threat to a distant time. Five times the phrase "in that day" appears, giving a glimpse of Egypt's spiritual future.
1. Egypt will fear Judah. (vv.16-17)
When the Messiah rules the world from David's throne in Jerusalem, all the nations, including Egypt, will demonstrate respect and respond accordingly.
2. Egypt will worship the LORD. (v.18)
The prediction is that there will be five key cities. The nation will abandon all false gods and be fully committed followers of Jesus, the Messiah.
3. Egypt will have its own altar. (vv.19-22)
With its own altar to worship the LORD and a public monument of testimony, the nation will openly declare to the world its embrace of the Messiah.
4. Egypt will be at peace. (v.23)
Given the current internal strife of that nation, it is hard to imagine them being at peace among themselves, let alone with their historic enemies. But when the Prince of Peace comes, these three-Assyria, Israel, and Egypt-will freely travel back and forth in peace.
5. Egypt will be blessed and be a blessing. (v.24)
One cannot read these words in verse 24 without remembering God's promise to Abraham in Genesis 12:3- "I will bless those who bless you, and him who dishonors you I will curse, and in you all the families of the earth shall be blessed."