Numbers 21:15

And at the stream of the brooks that goeth down to the dwelling of Ar, and lieth upon the border of Moab.

And at the stream of the brooks х wª'eshed (H793) hanªchaaliym (H5158)] - and at the pouring out of the torrents; i:e., the ravines of the mountains, through which the torrents issuing upon the plains or valleys, contribute by their confluence to form the Arnon (Mojib). 'The principal source of this river is not far from Kutraneh. About an hour eastward from the bridge it receives the waters of the Nahaliel or Lejum, which flow from the northeast in a deep channel. The Lejum receives the small brook Seil-el-Mekhreys, and then the Bahm' (Burckhardt's 'Travels'). The streams (torrents) of Arnon, therefore, refer to the Lejum and its tributaries. At the point of their confluence there is a level and extensive tract of rich meadow land, in the center of which rises a hill abounding with the ruined traces of ancient cultivation.

Ar, х `Aar (H6144)] - city. Gesenius considers it the same as х `iyr (H5892)] fortified city. "Ar of Moab" (Numbers 21:28), the metropolis of Moab, standing on the southern bank of the Arnon, and identical with the ruins of Rabba х Raabaah (H7235), great, or Rabbath-Moab; Greek, areopolis]. But this opinion of Gesenius is contrary to the clear statements of this passage. Compare Numbers 22:36; Deuteronomy 2:36, as to the geographical position of Ar, which was in the northern border of Moab, in the valley of the Arnon-on the left bank of that river, and consequently outside the boundary line; whereas Rabba stood in the center of the Moabite territory. That writer, with whom Robinson, Raumer, and others coincide, founds upon the statement in Numbers 21:26, where it is said that the Arnon, which with the towns on its banks, had been in the middle of the king of Moab's dominions, formed, after its conquest by Sihon, the northern boundary of the reduced kingdom; and hence, he concludes, on grammatical and historical grounds, that Ar and Rabba were identical. But what is called Rabba lies at a considerable distance from the Arnon; and therefore Ar, which was in the valley of the Arnon, must have been a different town (Hengstenberg, 'Pentateuch,' vol. 2:, p. 183; also, 'Balaam,' pp; 526-528; Kurtz, 'History of the Old Covenant,' vol. 3:, pp. 360-362; Robinson's 'Biblical Researches,' vol. 2:, p. 569; Raumer, 'Palestina,' p. 263).