Why did the Edomites become proud and arrogant?
The Edomites, descendants of Esau, lived as mountain dwellers. Climbing mountains daily built their physical stamina, making them a physically strong people. They built homes and vineyards in rocky cliffs. Because of that strength and security, they became proud and arrogant, boasting that no one could destroy them.
Les explains that the Edomites were the offspring of Esau and were mountain dwellers. Dwelling in the mountains meant they were in mighty good physical shape, because climbing those mountains every day built up physical stamina. They became a physically strong people, and they built their homes, vineyards, and so forth up in the cliffs of the rock. Consequently, with their physical stamina, they got proud and arrogant and said, nobody can destroy us. They were also anti-God and had no time for God. God said He would destroy them and not let them prosper. When Edom said they were impoverished but would return and build the desolate places, the Lord said they shall build, but He would throw them down. They would be called the border of wickedness and the people against whom the Lord has indignation forever. Even in all their pride and physical stamina, they were nothing under a sovereign God, while little, weak Israel could be made whatever God wanted.
And I hated Esau, and laid his mountains and his heritage waste for the dragons of the wilderness.