“Son of man, set your face against Mount Seir and prophesy against it, and declare that this is what the Lord GOD says:

Behold, I am against you,
     O Mount Seir.
I will stretch out My hand against you
     and make you a desolate waste.
I will turn your cities into ruins,
     and you will become a desolation.

Then you will know that I am the LORD.

Because you harbored an ancient hatred and delivered the Israelites over to the sword in the time of their disaster at the final stage of their punishment"

Ezek 35:2-5

First, a little background info. Who and where is Mount Seir?

Esau took his wives and sons and daughters and all the people of his household, along with his livestock, all his other animals, and all the property he had acquired in Canaan, and he moved to a land far away from his brother Jacob. For their possessions were too great for them to dwell together; the land where they stayed could not support them because of their livestock. So Esau (that is, Edom) settled in the area of Mount Seir.

Gen 36:6-8

Edom-Moab-830BCE.png, May 2023
Approximation of Edom, Moab, and Ammon in relation
to the divided kingdom of Israel

Mount Seir (Edom) is the ancient and biblical name for a mountainous region stretching between the Dead Sea and the Gulf of Aqaba - just east of modern day Israel in what is today the south-western part of Jordan.

Jordan.png, May 2023

The animosity Edom (Esau) has towards Israel (Jacob) goes back all the way to the incident where Esau accused Jacob of stealing his birthright. This animosity has expressed itself numerous times throughout history.

Here in Ezekiel 35, I believe we have a reflection of the most current hatred - "because you harbored an ancient hatred and delivered the Israelites over to the sword in the time of their disaster at the final stage of their punishment". 

According to the above verse, Mount Seir/Edom/Esau, because of an "ancient hatred", will be responsible for delivering Israel to the sword at the "final stage of their punishment".

And what will be the outcome?

“And you, son of man, prophesy to the mountains of Israel and say: O mountains of Israel, hear the word of the LORD. This is what the Lord GOD says: Because the enemy has said of you, ‘Aha! The ancient heights have become our possession,’ therefore prophesy and declare that this is what the Lord GOD says: Because they have made you desolate and have trampled you on every side, so that you became a possession of the rest of the nations and were taken up in slander by the lips of their talkers, therefore, O mountains of Israel, hear the word of the Lord GOD.

This is what the Lord GOD says to the mountains and hills, to the ravines and valleys, to the desolate ruins and abandoned cities, which have become a spoil and a mockery to the rest of the nations around you. Therefore this is what the Lord GOD says: Surely in My burning zeal I have spoken against the rest of the nations, and against all Edom, who took My land as their own possession with wholehearted joy and utter contempt, so that its pastureland became plunder."

Therefore, prophesy concerning the land of Israel and tell the mountains and hills, the ravines and valleys, that this is what the Lord GOD says: Behold, I have spoken in My burning zeal because you have endured the reproach of the nations.

Therefore this is what the Lord GOD says: I have sworn with an uplifted hand that surely the nations around you will endure reproach of their own."

Ezek 36:1-7

We should expect to see the relationship of the modern equivalents of Jacob and his brother Esau to experience flashes of hostility (we have) - and then to finally deteriorate to the point of betrayal.