What does Obadiah 1:4 mean?

In battle, high ground is a major advantage. Solid walls are also great benefits. Eagles' nests are notable for being built very high, and with very thick walls. For Edom, living in the mountains of Seir, it seemed as if they were invincible. Their caves were so well defended, and so high, it was as if they were eagles nesting in the stars. Edom also benefitted from busy trade and rich mineral resources. Arrogance and pride were part of their undoing.

The people of Edom were descended from Esau, the brother of Jacob. Jacob would eventually become Israel, the father of the Jewish people. So, from a national standpoint, Israel and Edom were brothers. And yet, for centuries, Edom had harassed and persecuted Israel. While Israel was abused by her neighbors, Edom enjoyed relative security.

Part of Obadiah's message to Edom is that they will suffer for the crimes committed against Israel. This judgment is coming from God, after years of sin and cruelty from the Edomites. The Old Testament warns many nations about coming wrath. And yet, no people are warned of God's vengeance as often as Edom.