What the Bible says about Edom's Confederacy Short-lived
(From Forerunner Commentary)
Even his friends, his allies in the conflict with Israel, know that Edom is not to be trusted. They are acquainted with the character of this ancient people, and thus they will do what needs to be done to keep him from dominating them and getting them involved beyond what they are prepared to do. His allies will secretly plan to destroy him. Any confederacy Esau has with others will be short-lived, and this is especially true knowing the deceitful character of his associates! They, too, are untrustworthy bedfellows.
Yet, they are unified in their hatred of Israel, and particularly of the people of Joseph. However, their united hatred will fail to overcome the descendants of Jacob. Ultimately, says verse 18, "The house of Jacob shall be a fire, and the house of Joseph a flame," suggesting that God will direct the nations of Joseph to take the lead in punishing Edom. The result will be that "the house of Esau shall be stubble; they shall kindle them and devour them. And no survivor shall remain of the house of Esau." What a dire fate!
Richard T. Ritenbaugh
All About Edom (Part Three): Obadiah