The word used here is the same word used elsewhere for the judges. Obadiah conveys the idea, found elsewhere in the Old Testament and in the New Testament, that God’s people will reign together with him. The Lord is the one who overthrows Edom, but Judah also has a small role; the people of God will not just be passively observant.
21 Saviors shall go up to Mount Zion to rule Mount Esau, and the kingdom shall be the LORD’s.