A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
deu 2:1THE STORY IS CONTINUED. (Deu. 2:1-37)
Then we turned, and took our journey into the wilderness by the way of the Red Sea--After their unsuccessful attack upon the Canaanites, the Israelites broke up their encampment at Kadesh, and journeying southward over the west desert of Tih as well as through the great valley of the Ghor and Arabah, they extended their removals as far as the gulf of Akaba.
we compassed mount Seir many days--In these few words Moses comprised the whole of that wandering nomadic life through which they passed during thirty-eight years, shifting from place to place, and regulating their stations by the prospect of pasturage and water. Within the interval they went northward a second time to Kadesh, but being refused a passage through Edom and opposed by the Canaanites and Amalekites, they again had no alternative but to traverse once more the great Arabah southwards to the Red Sea, where turning to the left and crossing the long, lofty mountain chain to the eastward of Ezion-geber (Num 21:4-5), they issued into the great and elevated plains, which are still traversed by the Syrian pilgrims in their way to Mecca. They appear to have followed northward nearly the same route, which is now taken by the Syrian hadji, along the western skirts of this great desert, near the mountains of Edom [ROBINSON]. It was on entering these plains they received the command, "Ye have compassed this mountain (this hilly tract, now Jebel Shera) long enough, turn ye northward" [Deu 2:3].
deu 2:4the children of Esau, which dwell in Seir . . . shall be afraid of you--The same people who had haughtily repelled the approach of the Israelites from the western frontier were alarmed now that they had come round upon the weak side of their country.
deu 2:5Meddle not with them--that is, "which dwell in Seir" (Deu 2:4) --for there was another branch of Esau's posterity, namely, the Amalekites, who were to be fought against and destroyed (Gen 36:12; Exo 17:14; Deu 25:17). But the people of Edom were not to be injured, either in their persons or property. And although the approach of so vast a nomadic horde as the Israelites naturally created apprehension, they were to take no advantage of the prevailing terror to compel the Edomites to accept whatever terms they imposed. They were merely to pass "through" or along their border, and to buy meat and water of them for money (Deu 2:6). The people, kinder than their king, did sell them bread, meat, fruits, and water in their passage along their border (Deu 2:29), in the same manner as the Syrian caravan of Mecca is now supplied by the people of the same mountains, who meet the pilgrims as at a fair or market on the hadji route [ROBINSON]. Although the Israelites still enjoyed a daily supply of the manna, there was no prohibition against their eating other food when opportunity afforded. Only they were not to cherish an inordinate desire for it. Water is a scarce commodity and is often paid for by travellers in those parts. It was the more incumbent on the Israelites to do so, as, by the blessing of God, they possessed plenty of means to purchase, and the long-continued experience of the extraordinary goodness of God to them, should inspire such confidence in Him as would suppress the smallest thought of resorting to fraud or violence in supplying their wants.
deu 2:8we passed . . . through the way of the plain--the Arabah or great valley, from Elath ("trees") (the Ailah of the Greeks and Romans). The site of it is marked by extensive mounds of rubbish.
Ezion-geber--now Akaba, both were within the territory of Edom; and after making a circuit of its southeastern boundary, the Israelites reached the border of Moab on the southeast of the Salt Sea. They had been forbidden by divine command to molest the Moabites in any way; and this special honor was conferred on that people not on their own account, for they were very wicked, but in virtue of their descent from Lot. (See on Deu 23:3). Their territory comprised the fine country on the south, and partly on the north of the Arnon. They had won it by their arms from the original inhabitants, the Emims, a race, terrible, as their name imports, for physical power and stature (Gen 14:5), in like manner as the Edomites had obtained their settlement by the overthrow of the original occupiers of Seir, the Horims (Gen 14:6), who were troglodytes, or dwellers in caves. Moses alluded to these circumstances to encourage his countrymen to believe that God would much more enable them to expel the wicked and accursed Canaanites. At that time, however, the Moabites, having lost the greater part of their possessions through the usurpations of Sihon, were reduced to the small but fertile region between the Zered and the Arnon.
deu 2:13Now rise up, and get you over the brook Zered--The southern border of Moab, Zered ("woody"), now Wady Ahsy, separates the modern district of Kerak from Jebal, and, indeed, forms a natural division of the country between the north and south. Ar, called in later times Rabbah, was the capital of Moab and situated twenty-five miles south of the Arnon on the banks of a small but shady stream, the Beni Hamed. It is here mentioned as representative of the country dependent on it, a rich and well-cultivated country, as appears from the numerous ruins of cities, as well as from the traces of tillage still visible on the fields.
deu 2:16all the men of war were consumed and dead from among the people--The outbreak at Kadesh on the false report of the spies had been the occasion of the fatal decree by which God doomed the whole grown-up population to die in the wilderness [Num 14:29]; but that outbreak only filled up the measure of their iniquities. For that generation, though not universally abandoned to heathenish and idolatrous practices, yet had all along displayed a fearful amount of ungodliness in the desert, which this history only hints at obscurely, but which is expressly asserted elsewhere (Eze 20:25-26; Amo 5:25, Amo 5:27; Act 7:42-43).
deu 2:19when thou comest nigh over against the children of Ammon, distress them not, nor meddle with them--The Ammonites, being kindred to the Moabites, were, from regard to the memory of their common ancestor, to remain undisturbed by the Israelites. The territory of this people had been directly north from that of Moab. It extended as far as the Jabbok, having been taken by them from a number of small Canaanitish tribes, namely, the Zamzummins, a bullying, presumptuous band of giants, as their name indicates; and the Avims, the aborigines of the district extending from Hazerim or Hazeroth (El Hudhera) even unto Azzah (Gaza), but of which they had been dispossessed by the Caphtorim (Philistines), who came out of Caphtor (Lower Egypt) and settled in the western coast of Palestine. The limits of the Ammonites were now compressed; but they still possessed the mountainous region beyond the Jabbok (Jos 11:2). What a strange insight does this parenthesis of four verses give into the early history of Palestine! How many successive wars of conquest had swept over its early state--what changes of dynasty among the Canaanitish tribes had taken place long prior to the transactions recorded in this history!
deu 2:24Rise ye up . . . and pass over the river Arnon--At its mouth, this stream is eighty-two feet wide and four deep. It flows in a channel banked by perpendicular cliffs of sandstone. At the date of the Israelitish migration to the east of the Jordan, the whole of the fine country lying between the Arnon and the Jabbok including the mountainous tract of Gilead, had been seized by the Amorites, who, being one of the nations doomed to destruction (see Deu 7:2; Deu 20:16), were utterly exterminated. Their country fell by right of conquest into the hands of the Israelites. Moses, however, considering this doom as referring solely to the Amorite possessions west of Jordan, sent a pacific message to Sihon, requesting permission to go through his territories, which lay on the east of that river. It is always customary to send messengers before to prepare the way; but the rejection of Moses' request by Sihon and his opposition to the advance of the Israelites (Num 21:23; Jdg 11:26) drew down on himself and his Amorite subjects the predicted doom on the first pitched battlefield with the Canaanites. It secured to Israel not only the possession of a fine and pastoral country, but, what was of more importance to them, a free access to the Jordan on the east.