Because the enemy hath said against you. The ground of Jehovah's purposed proceeding against Edom and the surrounding heathen peoples (Ezekiel 36:3, Ezekiel 36:5) is expressly declared to be the jubilation over the downfall of Israel, and the eagerness with which they sought to appropriate to themselves her forsaken land.
Aha! Exulting over Israel's misfortune (comp. Ezekiel 25:3; Psalms 40:16). The ancient high places, which Israel's enemies fancied had become theirs in possession, were probably "the everlasting hills" of Genesis 49:26 and Deuteronomy 33:15, the principal mountains of Palestine, which, as Havernick finely observes, were "the honorable witnesses and indestructible monuments of that ancient blessing spoken by Israel's ancestor, and still resting on the people;" and to assail which was, in consequence, not only to sin against Jehovah, but to attempt an enterprise foredoomed to failure and shame.
At the same time, Plumptre's suggestion ('Ezekiel: an Ideal Biography,' Expositor, vol. 8.284; and Unpublished Notes) is not without plausibility, that, considering the special significance of the term bamoth in Ezekiel, the phrase should be held as referring to the sanctuaries which stood upon those heights—including, of course, the chief sanctuary, or temple (Schroder); in support of which the dean cites the frequency with which the enemies of Israel, as, for instance, the Assyrians and the Moabites, in their inscriptions, boasted that they had captured these sanctuaries.