The Prophecies of Amos: Oracles against the Nations

In this chapter, we will introduce Amos’s famous prophecies against the surrounding nations, which make up the first twenty verses and comprise a “set-up” for his prime audience in Shomeron. Amos delivers oracles against Aram, Peleshet, Tzor, Edom, Ammon and Moav, then Yehuda before zeroing in on Yisrael.  Why does Amos deliver prophecies foretelling punishment specifically to these nations? Why does he not mention Assyria or Egypt, two major (and threatening) superpowers? What is his prophetic purpose, and what is the nature of these "prophecies to the nations?" 

Looking at the map, we see that as the people of Israel hear the prophecies of doom for their enemies, they feel some relief. And then they realize that they are being entrapped instead of protected, and destruction is looming closer and closer.