v1: Words addressed to Babylon, as previously in chapters 13-14. It is described as the Desert by the Sea, a flat country, with many lakes, watered by smaller rivers flowing into the Euphrates. The whirlwinds were the Medes and Persians, attacking from the desert.
v2: The distressing vision. There were two traitors, officers of the king of Babylon, who defected to Cyrus, and then led enemy troops into the palace, killing Belshazzar, Dan 5.28, 30.
Babylon had previously defeated Israel, 2 Kings 17.24,30-31) and many other lands; the kingdom of Babylon was then taken over by the Medes and Persians, just as Babylon had taken over the Assyrian empire.
Babylon's cruelty ended, ending the sorrow and sighing it caused.
v3-4: Compare Dan 5.6; the prophet was greatly disturbed by what he saw. Isaiah was called to declare the things he saw; he could not remain unmoved by these things.
v5: Belshazzar had prepared a table with food and drink, while others watched out for him.
v6-7: Isaiah watched as the Lord showed him events unfolding. The Medes and Persians are represented by the pair of horsemen.
v8: The faithful watchman, always alert.
v9: The man in the chariot with its horses may have been the small party sent to kill Belshazzar, as well as the picture of the Medes and Persians. They joined together, to defeat the might of Babylon.
Babylon was defeated suddenly, and Belshazzar killed, and kingdom given over to the Medes and Persians. Their idols were left broken, having proved useless.
v10: Encouragement for Jewish captives, who had been "crushed" by the power and cruelty of Babylon. These events were directed by the Lord God of Israel. The return of the captives to their homeland moved a little closer.
v11-12: Addressed to Edom (Dumah), who lived in the land of Seir. They would also be threatened by the invasion of Babylon, bringing "night" to the whole nation. If, however, they returned to the true God, then a new morning would arrive.
v13-15: To Arabia, where nomadic peoples passed through. It was here also that fugitives from the attacks of Babylon journeyed.
v16-17: The word of God cannot fail; here He placed a time limit on the defeat of Babylon (Kedar).
Through all these prophecies of different nations, it is the God of Israel at work, and the people of God who remain in His heart.