For thy violence against thy brother Jacob shame shall cover thee, and thou shalt be cut off for ever.
For thy violence against thy brother Jacob. Obadiah here confirms afresh Joel's prophecy (Joel 3:19), "Edom shall be a desolate wilderness, for the violence against the children of Judah." This aggravates the sin of Esau, that it was against him, who was his brother by birth and by circumcision. The posterity of Esau followed in the steps of their father's hatred to Jacob by violence against Jacob's seed (Genesis 27:41).
Jacob - not merely his own brother, but his twin brother: hence, the name Jacob is here put emphatically, not Israel. Compare Deuteronomy 23:7 for the opposite feeling which Jacob's seed was commanded to entertain toward Edom's, "Thou shalt not abhor an Edomite; for he is thy brother."
Shame shall cover thee - (Psalms 35:26, "Let them be clothed with shame;" Psalms 69:7, "Shame hath covered my face").
And thou shalt be cut off forever - (Isaiah 34:10; Ezekiel 35:9; Malachi 1:4). Idumea, as a nation, should be "cut off forever," though the land should be again inhabited.