The Prophet Ovadiah was a convert from the religion practiced in Edom. He lived at the time of Eliyahu HaNavi and his disciple, Elisha, and is identified as the Administrator in Achav's and Izevel's Palace ("Melachim"/Kings I, 18:3). He is described there as "fearing the L-rd greatly."
Ovadiah's great merit was that he risked his life to maintain 100 prophets in a cave, providing them with all their needs, at a time that the Prophets were under tremendous pressure and great danger from the Palace.
Ovadiah was chosen as the Prophet to deliver the message of Edom's doom; perhaps because he grew up there and was intimately knowledgeable concerning the conspiracies and evils of the royal, the political and the military complex.
The Book of Ovadiah consists of only one Chapter.
Edom had relied on its location to guarantee its protection from attack. But HaShem says through Ovadiah,
"The wickedness of your heart enticed you,
"Shame shall cover you,
And the ones who will bring Esav down will be the descendants of your brother, Yaakov.
"And the house of Yaakov shall be a fire,
And ultimately, the returning Jewish population from all over the world will displace Esav, and the L-rd's Kingdom shall prevail.
"And the returning host of the Congregation of Israel,