The following is an excerpt from the introduction of the book of Obadiah provided by the Holman Christian Standard Bible. After reading the book and commentary, I could not think of anything that was not already said in the introduction.

“Obadiah is the shortest book of the Minor Prophets. No other source mentions Obadiah, although the name is a common one in the Old Testament. Meaning “servant of Yahweh,” it reflects his parents’ faith and spiritual ambitions for their child. The title, “The vision of Obadiah,” turns attention to the divine author, “vision” being a technical term for a prophetic revelation received from God. Obadiah had angry, bitter words for Edom, a nation that no longer exists in our day. Why would God inspire a prophet to write even a short book with its main theme about such an obscure nation? Obadiah was outraged about a time when the Edomites should have come to Judah’s aid as allies in an alien attack but instead took advantage of the situation. Edom represents all those who oppose the purposes of the Lord. The perspective shifts at Obadiah 15-21 from Edom alone to Edom and all the nations. Edom’s treachery and overconfidence made it a perfect example for Obadiah. Whatever Obadiah said about Edom applies equally well to any nation that sets itself against the Lord and His people. The Lord’s sovereignty over the nations is evident throughout the book. He summoned them to assemble against Edom, He challenged Edom’s haughty attitude, He threatened to cut off all hope of rescue, and He promised a day when He would set all things right, restoring Israel and Judah to their former territories.
In Obadiah’s contrasting of the destiny of the people of God and that of the enemies of God, he reminds us of the severity of the sins of arrogance, pride, and betrayal. God will always judge the proud, arrogant ones, and those who betray another will themselves be betrayed.
Obadiah pointedly proclaimed that good will triumph at the end of the day, but it is God’s goodness that triumphs, not mankinds. Throughout the book of Obadiah, God is the central figure. God defines the rules, chooses His own people, and dispenses judgment. He is in control of history. Surely the one who rules the nations also is able to care for His people.”