A prophecy against the Desert by the Sea.

Isaiah 21:1-17
A prophecy against the Desert by the Sea.
Elam, attack! Media, lay siege! I will bring to an end all the groaning she caused.
My people who are crushed on the threshing floor,  I tell you what I have heard from the Lord Almighty, from the God of Israel.
This is what the Lord says to me: “Within one year, as a servant bound by contract would count it, all the splendor of Kedar will come to an end.
The survivors of the archers, the warriors of Kedar, will be few.” The Lord, the God of Israel, has spoken.
The 'wilderness' or 'desert by the sea' is Babylonia. The downfall on Babylon will be good news to the captives from Israel. Even so, Isaiah is appalled by what he foresees. Being a 'seer' is a painful and costly business.
There is temporary respite for Edom - but judgment was to follow.
Not even the remote tribes of Arabia will escape the long arm of Assyria. This prophecy became reality when Sargon attacked Arabia in 715 BC.
Why?
The emporary respite for Edom - but judgment was to follow. Do not too joy when heard some good news, may be the judgment is follow
How?