What is "Rabah"?
Radak: It is the capitol [of Amon].
Why will it be a habitat of camels and flocks?
Radak: After a while, Madai u'Faras will leave on their own, or due to another nation that will come against them. It will be desolate, and a habitat of camels and flocks.
Malbim: Since Bnei Kedar 1 engaged in camels and flocks, the capitol will be for camels and the Klal of the country for flocks.
Radak (Yirmeyah 49:28): Kedar is from Bnei Kedem.
How will you know that I am Hashem?
Radak: You will know that I have all ability, and I oversee everything. What came upon Yisrael was due to their sin - what will come upon you is due to your Simchah over [the destruction of] Eretz Yisrael.
