Num 34:3-5
The southern boundary is the same as that given in Jos 15:2-4 as the boundary of the territory of the tribe of Judah. We have first the general description, “The south side shall be to you from the desert of Zin on the sides of Edom onwards,” i.e., the land was to extend towards the south as far as the desert of Zin on the sides of Edom. על־ידי, “on the sides,” differs in this respect from על־יד, “on the side” (Exo 2:5; Jos 15:46; 2Sa 15:2), that the latter is used to designate contact at a single point or along a short line; the former, contact for a long distance or throughout the whole extent (= כּל־יד, Deu 2:37). “On the sides of Edom” signifies, therefore, that the desert of Zin stretched along the side of Edom, and Canaan was separated from Edom by the desert of Zin. From this it follows still further, that Edom in this passage is not the mountains of Edom, which had their western boundary on the Arabah, but the country to the south of the desert of Zin or Wady Murreh, viz., the mountain land of the Azazimeh, which still bears the name of Seir or Serr among the Arabs (see Seetzen and Rowland in Ritter's Erdk. xiv. pp. 840 and 1087). The statement in Jos 15:1 also agrees with this, viz., that Judah’s inheritance was “to the territory of Edom, the desert of Zin towards the south,” according to which the desert of Zin was also to divide the territory of Edom from that of the tribe of Judah (see the remarks on Num 14:45). With Num 34:3 the more minute description of the southern boundary line commences: “The south border shall be from the end of the Salt Sea eastward,” i.e., start from “the tongue which turns to the south” (Jos 15:2), from the southern point of the Dead Sea, where there is now a salt marsh with the salt mountain at the south-west border of the lake. “And turn to the south side (מנּגב) of the ascent of Akrabbim” (ascensus scorpionum), i.e., hardly “the steep pass of es Sufah, 1434 feet in height, which leads in a south-westerly direction from the Dead Sea along the northern side of Wady Fikreh, a wady three-quarters of an hour’s journey in breadth, and over which the road from Petra to Heshbon passes,” as Knobel maintains; for the expression נסב (turn), in Num 34:4, according to which the southern border turned at the height of Akrabbim, that is to say, did not go any farther in the direction from N.E. to S.W. than from the southern extremity of the Salt Sea to this point, and was then continued in a straight line from east to west, is not at all applicable to the position of this pass, since there would be no bend whatever in the boundary line at the pass of es Sufah, if it ran from the Arabah through Wady Fikreh, and so across to Kadesh. The “height of Akrabbim,” from which the country round was afterwards called Akrabattine, Akrabatene (1 Macc. 5:4; Josephus,Ant. 12:8, 1), is most probably the lofty row of “white cliffs” of sixty or eighty feet in height, which run obliquely across the Arabah at a distance of about eight miles below the Dead Sea and, as seen from the south-west point of the Dead Sea, appear to shut in the Ghor, and which form the dividing line between the two sides of the great valley, which is called el Ghor on one side, and el Araba on the other (Robinson, ii. 489, 494, 502). Consequently it was not the Wady Fikreh, but a wady which opened into the Arabah somewhat farther to the south, possibly the southern branch of the Wady Murreh itself, which formed the actual boundary.
“And shall pass over to Zin” (i.e., the desert of Zin, the great Wady Murreh, see at Num 14:21), “and its going forth shall be to the south of Kadesh-barnea,” at the western extremity of the desert of Zin (see at Num 20:16). From this point the boundary went farther out (יצא) “to Hazar-Addar, and over (עבר) to Azmon.” According to Jos 15:3-4, it went to the south of Kadesh-barnea over (עבר) to Hezron, and ascended (עלה) to Addar, and then turned to Karkaa, and went over to Azmon. Consequently Hazar-Addar corresponds to Hezron and Addar (in Joshua); probably the two places were so close to each other that they could be joined together. Neither of them has been discovered yet. This also applies to Karkaa and Azmon. The latter name reminds us of the Bedouin tribe Azazimeh, inhabiting the mountains in the southern part of the desert of Zin (Robinson, i. pp. 274, 283, 287; Seetzen, iii. pp. 45, 47). Azmon is probably to be sought for near the Wady el Ain, to the west of the Hebron road, and not far from its entrance into the Wady el Arish; for this is “the river (brook) of Egypt,” to which the boundary turned from Azmon, and through which it had “its outgoings at the sea,” i.e., terminated at the Mediterranean Sea. The “brook of Egypt,” therefore, is frequently spoken of as the southern boundary of the land of Israel (1Ki 8:65; 2Ki 24:7; 2Ch 7:8, and Isa 27:12, where the lxx express the name by Ῥινοκοροῦρα). Hence the southern boundary ran, throughout its whole length, from the Arabah on the east to the Mediterranean on the west, along valleys which form a natural division, and constitute more or less the boundary line between the desert and the cultivated land.