Obadiah 1:18

Here again the Prophet meets a doubt, which might come into the mind of each of them; for the Idumeans were flourishing, and their condition was independent, when the Israelites as well as the Jews were led into exile, and Jerusalem with its temple was destroyed. They might under such circumstances despair; but the Prophet shows, that though for a time the house of Jacob seemed to be dead, yet a fire would be kindled, which would consume the Idumeans, though they were then proud of their power and their wealth, and also of the prosperous issue of the victory over the Jews, for they had been enriched, and well as the Assyrians, by the overthrow of their brethren. A similar mode of speaking Isaiah also adopts; though he directs his discourse, not to the Idumeans, but to others, yet his manner of speaking is the same when he says, that God, the light of Israel, would be a fire and a flame to consume the wicked, (Isaiah 29:6.)

But this was fulfilled, when the Lord avenged the cruelty of Edom, though the Jews were then in exile and could not move a finger, when they were without arms, yea, when they were miserable slaves: the Idumeans were even then consumed, by what fire? how was this burning kindled? Even then the house of Jacob and the house of Joseph were like a fire and a flame The cause of this ruin, it is true, did not immediately appear to the Idumeans: but we must here look to the purpose of God. Why did God with so much severity punish the Idemeans? Because he intended by this example to show how much he loved his Church. Since then their cruelty was the cause of ruin to the Idumeans, rightly does the prophet say, that the house of Jacob and the house of Joseph would be like a fire and a flame to consume the Idumeans. And it was not a small solace to the miserable exiles, when they understood, that they were still regarded by God in their depressed condition. Inasmuch then as they were exposed to the reproach and ridicule of all, it pleased God to testify that they were the objects of his care, and that he would, for their sake, destroy whole nations even those who then gloried in their power. We now then see why the Prophet adopted this figurative language. By the house of Joseph, he means as we have said elsewhere the kingdom of Israel; he mentions a part for the whole. It follows —