Ezekiel 25:12

Edom, so named from Esau, consisted of various tribes enumerated in Genesis 36. The Edomites became a powerful nation before the Israelites came out of Egypt. David conquered them, but in the reign of Joram they rebelled and were not again subdued 2 Kings 8:20. Under the name of Idumea the land was conquered by John Hyrcanus (compare Ezekiel 25:14), when many of the people adopted the religion of the Jews. In later times the Idumean Herod became king of Palestine, reckoning himself as a Jew. Mount Seir, deserted by its original inhabitants, was occupied by a tribe of Arabians (the Nabatheans), under whelm Petra rose and continued a flourishing city under Roman dominion, until the tide of Mahometan conquest brought it to that ruin in which Edom at last found the complete fulfillment of the prophecies uttered against it Ezekiel 35:1.

Taking vengeance - Referring to the wrong done by Jacob to Esau Genesis 27:36.