Because

Ezekiel 25:8
This is what the Lord GOD says: 'Because Moab and Seir said, "Look, the house of Judah is like all the other nations, "

Ezekiel 35:1-15
Moreover, the word of the LORD came to me, saying, . . .

2 Chronicles 28:17, 18
The Edomites had again come and attacked Judah and carried away captives. . . .

Psalm 137:7
Remember, O LORD, the sons of Edom on the day Jerusalem fell: "Destroy it, " they said, "tear it down to its foundations!"

Jeremiah 49:7
Concerning Edom, this is what the LORD of Hosts says: "Is there no longer wisdom in Teman? Has counsel perished from the prudent? Has their wisdom decayed?

Genesis 27:41, 42
Esau held a grudge against Jacob because of the blessing his father had given him. And Esau said in his heart: "The days of mourning for my father are at hand; then I will kill my brother Jacob." . . .

Amos 1:11, 12
This is what The LORD says: "For three transgressions of Edom, even four, I will not revoke My judgment, because he pursued his brother with the sword and stifled all compassion; his anger raged continually, and his fury flamed incessantly. . . .

Obadiah 1:10-16
Because of the violence against your brother Jacob, you will be covered with shame and cut off forever. . . .