Heidegger's Bible Handbook: Obadiah: Argument

2.  Edom, to whom the Prophecy is directed, who was he?  The Argument of the Prophecy.

Moreover, that Prophecy is directed לֶאֱדוֹם, to Edom, Obadiah 1.  By which name the Roman Empire is designated, the Jews insist, because just as the Idumeans of old were, so now the Romans, and indeed the Christians, all are opposed to the law of God.  But that name agrees more truly with the Jews themselves, from which time they united the Idumeans with themselves, and were under King Herod of Idumea and his sons:  and they were led by the same spirit toward the covenant of God and their brethren confession Christ, as Esau, or Edom, was of old, towards Jacob.  Therefore, by Edom is understood, sometimes literally the posterity of Esau; sometimes the Jewish people selling the primogeniture with a profanity similar to that of Esau,[1] mixed with the Idumeans, governed by the Idumeans, persecuting their own brethren; sometimes false brethren, and the Roman Pope himself, imitating the Jews and the Gentiles as persecutor of believers.  But here, under the name of Edom, obliteration is denounced literally against the Idumeans, and almost literally against the Jews, mixed with the Idumeans in the time of Christ, and furnished with the character of the Idumeans:  contrariwise, to the people of God, under the name of Zion, is promised liberation from captivity, restoration of their former inheritance, and the kingdom of God.  And in this consists a summary of the book.

[1] See Genesis 25:29-34.