Obadiah names himself
The opening line calls the book a vision of Obadiah, so the traditional and most straightforward answer is that the prophet Obadiah wrote it (Obadiah 1:1). His name means “servant of the Lord”, which fits the role he takes throughout the book.
Unlike Isaiah, Jeremiah, or Ezekiel, Obadiah doesn't tell readers where he lived, who his father was, or when he began prophesying. That silence can feel frustrating. Yet the book's focus isn't on building Obadiah's reputation. It points beyond the messenger to the Lord who speaks.
The vision of Obadiah. Thus saith the Lord God concerning Edom; We have heard a rumour from the Lord, and an ambassador is sent among the heathen, Arise ye, and let us rise up against her in battle.
Not every Obadiah in Scripture
Several men in the Old Testament share this name. One Obadiah served in King Ahab's household and protected a hundred prophets when Jezebel was hunting them (1 Kings 18:3-4). Another appears among King David's officials (1 Chronicles 27:19).
Scripture never says that either man wrote this prophetic book. The Obadiah who wrote it may have been one of them, but there isn't enough evidence to say with confidence. It is wiser to distinguish what the text tells us from what people have wondered about.
His message was for Edom
Obadiah's prophecy addresses Edom, the nation descended from Esau, Jacob's brother. Instead of helping Judah when Jerusalem suffered, Edom acted proudly and took advantage of its neighbour's disaster (Obadiah 1:10-12).
God's words through Obadiah show that cruelty, pride, and delight in another people's pain do not escape his notice. Edom trusted its mountain strongholds, but the Lord declared that no secure-looking place could protect a nation that set itself against him (Obadiah 1:3-4).
For thy violence against thy brother Jacob shame shall cover thee, and thou shalt be cut off for ever.
A short book with lasting hope
Obadiah is the shortest book in the Old Testament, but it ends with more than judgement. God promises deliverance for his people and declares that the kingdom belongs to the Lord (Obadiah 1:17, Obadiah 1:21).
So, while we don't know much about the man Obadiah, we do know the purpose of his book. Through an otherwise hidden servant, God spoke about justice, humility, and his final rule. Reading the whole chapter is a good way to hear that message for yourself.
And saviours shall come up on mount Zion to judge the mount of Esau; and the kingdom shall be the Lord's.