Obadiah 21 is the triumphant conclusion of this short prophecy: "Then saviors shall come to Mount Zion to judge the mountains of Esau; and the kingdom shall be the LORD's." The book began with God saying that He is the prime mover of world events, and it ends with, "God rules all things!" As the Psalms often declare, "The LORD reigns!" (see Psalm 93:1; 96:10; 97:1; 99:1).
Herbert Armstrong, in Mystery of the Ages (pages 239-241), explains the "saviors" to be glorified members of God's church. He calls them "co-saviors with Christ." This interpretation is certainly a possibility. We should not, however, understand this to mean that resurrected Christians will in any way provide for spiritual salvation as Jesus Christ did through His sacrificial death by crucifixion. Instead, it appears that these saviors rescue or deliver people; they help them not only to survive but to thrive under God's rule.
Obadiah 21 parallels a prophecy of the Millennium in Isaiah 30:21: "Your ears shall hear a word behind you saying, 'This is the way, walk in it,' whenever you turn to the right hand or whenever you turn to the left." These saviors will assist Jesus Christ in delivering people from a way of life that is contrary to God's perfect way. They will help the nations to learn peace and righteousness, a way that produces loving harmony between brothers.
Zechariah 14:1-3, 5, 9 ties in beautifully with the last verse of Obadiah:
Behold, the day of the LORD is coming, and your spoil will be divided in your midst. For I will gather all the nations to battle against Jerusalem. . . . Then the LORD will go forth and fight against those nations, as He fights in the day of battle. . . . Thus the LORD my God will come, and all the saints with You [Him]. . . . And the LORD shall be King over all the earth.
When Jesus Christ returns, He comes with His saints—the saviors of Obadiah 21. They, along with Jesus Christ, will come and "judge the mountains of Esau." As part of God's government, their job will be to help govern the entire earth. This is the essence of the Kingdom of God, a time when mankind—even the Edomites, should any survive—will finally submit to God's rule.
Richard T. Ritenbaugh
All About Edom (Part Five): Obadiah and God's Judgment