This very short oracle is a bit of a mystery, as there is no known town or settlement inside of Edom that was called Dumah. However dumah means silence, hidden meaning or concealment, it may have been intended to be paronomasia, “The Oracle Concerning Silence”. This, however, would make it stand out as the only Isaiah Oracle that is not addressed to a proper noun. So the scholars argue.

The oracle concerning Dumah. 

One is calling to me from Seir,  “Watchman, what of the night? Watchman, what of the night?” 12 The watchman says:  “Morning comes, and also the night. If you will inquire, inquire; come back again.” Is. 21:11-12

FYI: Dumah was one the of sons of Ishmael [Gen 25:14-16]

  A village in the south of Judah  [Josh 15: 52-54]

Dumah appears only two other times in the whole Old Testament both are in the Psalms where they are a poetic reference to a place where the dead are.

If the LORD had not been my help, my soul would soon have dwelt in the land of silence. Psa. 94:17

The dead do not praise the LORD, nor do any that go down into silence. Psa. 115:17

There is one calling from Seir which would be Mount Seir the stronghold of Edom. The Edomites were the descendants of Esau. Under the Roman Empire,  Mount Seir became the city of Petra. In antiquity, it was a major stopping place on the spice road from southern Arabia. From the time of Saul, Edom had been vassals to Judah.

FYI: Petra has been used as a backdrop location for movies such as; Indiana Jones and the Last Crusade, Arabian Nights, Passion in the Desert, Mortal Kombat: Annihilation, Sinbad and the Eye of the Tiger, The Mummy Returns and Transformers: Revenge of the Fallen.

Someone from Edom is calling out to either God or Isaiah as to how far the night has gone. Some interpret this “night” as Babylonian oppression.

The prophecy seems to be saying that the watchman of Mount Seir is silent or possibly dead. The watchmen were the guardians of the night. It was their job to watch for fires, thieves, or invading armies. They are the ones who know what is happening. They are asked by one from Edom, what is happening in the night. Where only one person asked, “What of the night?”  in verse 12 the “inquire” is in the plural, which only adds to the confusion of what is meant. It is like the gatekeeper in the Wizard of Oz who tells Dorothy too, “Come back tomorrow,” when he knew full well that tomorrow he would not open the gate either. They may inquire, again, but the answer will always be silence.

The Dumah oracle is not the only place where Isaiah speaks of Edom. In chapter 34 He says, the night and day will not be quenched, and like Babylon, in The Revelation, the smoke goes up forever. [Rev. 19:3]

8   For the LORD has a day of vengeance, a year of recompense for the cause of Zion.  9 And the streams of Edom shall be turned into pitch, and her soil into brimstone; her land shall become burning pitch.  10 Night and day it shall not be quenched; its smoke shall go up for ever. From generation to generation it shall lie waste; none shall pass through it for ever and ever.  11 But the hawk and the porcupine shall possess it, the owl and the raven shall dwell in it. He shall stretch the line of confusion over it, and the plummet of chaos over its nobles.  12 They shall name it No Kingdom There, and all its princes shall be nothing. Is 34:8-12

Why this animosity toward Edom? According to the Psalmist, Jeremiah, and Obadiah, the Edomites helped the Babylonians plunder and slaughter Jerusalem. [Psa. 137:7; 1 Jer. 49:7–22 Obad. 1:11–14] After the Jews were deported to Babylon many Edomites moved up around Hebron, where they eventually commingled and intermarried with the Jews, the Romans called these people the Idumea, (which is where King Herod came from). After Jerusalem was destroyed in 70AD all records of the Idomaeans as a separate people are lost.

Messiah had warned the Jews that Jerusalem would fall within one generation. [Matt 24] Because of the warning the Believers had left the city and crossed the Jordan to wait the war out in Pella. However no warning was given to the Idumaeans, they perished along with the Jews in Jerusalem. Josephus tells us that one night the gates were opened to the Idumaeans. After that, the city gates were sealed along with the fate of everyone inside the city.

Josephus War Book 4 chapter 5