Numbers 21:13

on the other side of Arnon This probably means north of it, the direction being considered from the point of view of the march; cf. Judges 11:18.

The Arnon, now known as the Wady-el-Mojib, was a large stream which flowed westward into the Dead Sea at about the middle point of its eastern side. For a fuller description see on Numbers 21:14.

which is in the wilderness i.e. that part of it which is in the wilderness. The clause defines more exactly one of the many streams which compose the river, perhaps the Wady Wâleh which flows into it from the north about 4½ miles from its mouth (see Enc. Bibl.[Note: nc. Bibl. Encyclopaedia Biblica.] 3170 note 1). It shews that the Israelites were still eastward of Moab in the district of the upper reaches of the river and its tributaries, all of which might loosely be called the Arnon (G. A. Smith, H. G.[Note:. G. Historical Geography of the Holy Land.] 558). This district, here and in Numbers 21:23 called -the wilderness," is named -the wilderness of Kedemoth" in Deuteronomy 2:26.

that cometh out from the territory of the Amorites This describes the wilderness, not the Arnon. The uncultivated region of the upper Arnon stretched away eastward from the Amorite country.

Arnon is the border of Moab i.e. the northern border. At an earlier time the Moabites had possessed some land north of the river, and the Ammonites had lived north of them as far as the Jabbok. But shortly before the arrival of the Israelites, the Amorites had driven the Ammonites eastward into the desert, and the Moabites to the south of the Arnon (Numbers 21:26; Judges 11:22). Thus directly the Israelites crossed the Arnon they were on the eastern border of the Amorites" country, and, with a view to striking westward to the Jordan, they asked Sihon's permission to pass through his country. In Deuteronomy 2:26-37 this and the subsequent fight with the Amorites are related correctly at this point. But in Num. the journey through the Amorite land is related (Numbers 21:16) before the hostility of Sihon is described.