My sword shall be bathed in heaven; rather, has been bathed, or has been made drunken ( ἐνεθύσθη, LXX.) in heaven. Some suppose a reference to the old" war in heaven," when the sword of Divine justice was drawn against the devil and his angels.
Others regard the sword now to be used against the Idumeans as first, in heaven, "made drunken" with the Divine anger. It shall come down upon Idumea (comp. Isaiah 63:1-6). The Edomites first showed themselves enemies of Israel when they refused to allow the Israelites, under Moses, "a passage through their border" (Numbers 20:14-21).
David subdued them (2 Samuel 9:1-13:14); but they revolted from Jehoram (2 Chronicles 21:8-10), and were thenceforward among the most bitter adversaries of the southern kingdom. They "smote Judah" in the reign of Ahaz (2 Chronicles 28:17), and were always ready to "shed the blood of the children of Israel by the force of the sword in the time of their calamity" (Ezekiel 35:5).
Amos speaks of them very much in the same tone as Isaiah (Amos 1:11, Amos 1:12). They ultimately "filled up the measure of their iniquities" by open rejoicing when Jerusalem was destroyed, and the people led away captive by Nebuchadnezzar (Psalms 137:7; Obadiah 1:10-14; Lamentations 4:21, Lamentations 4:22; Ezekiel 35:10-13).
In the present passage we must regard the Edomites as representative of the enemies of God's people generally (see the introductory paragraph). The people of my curse; i.e. "the people on whom I have laid a curse"—the Edomites.
Esau was to "serve" Jacob (Genesis 25:23; Genesis 27:40), Edom to be "a possession" for Judah (Numbers 24:18). God had said of Edom, probably before Isaiah uttered the present prophecy, "For three transgressions of Edom, and for four, I will not turn away the punishment thereof … but I will send a fire upon Teman, which shall devour the palaces of Bozrah" (Amos 1:11, Amos 1:12).
Thus Edom was under a curse.