Behold, I will make you small among the nations; you shall be utterly despised. The pride of your heart has deceived you, you who live in the clefts of the rock, in your lofty dwelling, who say in your heart, “Who will bring me down to the ground?”
Obadiah 1:2-3

That which you hold most dearly is the very thing you must give up for God. Edom refused to let Israel pass because they feared Israel would once again take away their inheritance (remember Jacob and Esau?), but because they refused to risk their inheritance on behalf of Israel, God took their inheritance away anyway.