In my last post, we learned of Another Prophecy Against the Desert by the Sea (Bavel) in Yesha’yahu 21:1-10. In this post, we learn of A Prophecy Against Dumah and Arabia in Yesha’yahu 21:11-17.
11 A prophecy about Dumah: Someone is calling to me from Se‘ir: “Watchman, how much longer is it night? Watchman, how much longer is it night?” 12 The watchman answers: “Morning is coming, but also the night. If you want to ask, ask! Come back again!”
Dumah is an oasis town in north-central Saudi Arabia near the southern end of the Wadi Sirhan. Its association with the Kedarite confederacy of Bedouin tribes of that region (Genesis 25:13) may explain the place name’s tie to Edom. There may also be a pun expressed here in the Hebrew of this word (duma), which means “silence,” and Edom.
Some people may ask in our day, Watchman, how much longer is it night? We are to be the watchmen, for Yeshua said we are to watch for His coming (Matthew 24:42). If we believed Yeshua could come back today, there would be no more negative talk, no more gossip, slander, or innuendo among us. That is why John tells us that whoever has the hope of Yeshua coming purifies himself (1 John 3:3).
As an introduction to our next passage, D’dan, Teima, and Kedar are references to geographical and political entities in northern Arabia. They were likely allies of Bavel during the eighth century BCE. These tribes were defeated by Ashurim between 691-689 BCE.
13 A prophecy about Arabia: You caravans of D’danim will camp in the desert growth of Arabia. 14 Bring water to the thirsty, you who live in Teima, greet the fugitives with food;
Comprising territories claimed by various Bedouin tribal groups, Arabia was an area that Ashurim kings listed as a part of their empire but never truly controlled. The Arab tribes occupied the region between the southern Negev and the north-central portion of the Arabian Peninsula. The D’danim tribes used northwest Arabia as their base of operations. They operated as caravaneers with contacts in Syria, Phoenicia, and Palestine. Teima has long been identified with the oasis city of Tayma, located on the western border of the North Arabian Desert. It lies at the crossroads of three major trade routes of the “incense road” from South Arabia to Syria, Mesopotamia and eastern Arabia. 
15 because they are fleeing the sword, the drawn sword, the bent bow and the press of battle. 16 For this is what Adonai has told me: “Within a year [and not a day more], as if a hired worker were keeping track of the time, the glory of Kedar will come to an end.
Tied to the Ishmaelites in Genesis 25:13, the Kedarim functioned as sheep breeders and caravaneers at least as late as the Hellenistic period. There is clear evidence of ties between Kedar and Tema in Bavlim economic texts.
17 Few of Kedar’s valiant archers will be left.” Adonai, the God of Isra’el, has spoken. ~ Isaiah 21:11-17 (CJB)
In essence, this prophecy says that within one year, Arabia would be destroyed. Indeed, exactly one year from the time it was given, in the year 716 BCE, Sargon, the Ashurim took control of Arabia.
In my next post, we will explore in A Prophecy Against the Valley of Vision ~ Part 1 in Yesha’yahu 22.
 The IVP Bible Background Commentary – Old Testament.