Arnon

The Arnon is the river that drains into the Dead Sea from the east and forms Moab's northern frontier. Across the UPDV it serves as a boundary line: between Moab and the Amorites before Israel's arrival, between conquered and unconquered land in the trans-Jordan campaign, between the tribal allotments of Reuben and Gad and the territory still held by Ammon, and — much later — as the place where Moabite refugees gather as their kingdom collapses.

The Border between Moab and the Amorites

The Arnon enters the narrative as the surveyed line dividing two kingdoms. When Israel reaches it on the wilderness march, the text fixes the river's role in a single clause: "the Arnon is the border of Moab, between Moab and the Amorites" (Nu 21:13). The watercourse runs out of Amorite territory and meets the Moabite frontier on its southern bank, and Israel halts on the far side of it in the wilderness.

The Arnon's status as a contested boundary is older than Israel's arrival. Before the conquest, Sihon king of the Amorites had pushed the line south at Moab's expense: "Heshbon was the city of Sihon the king of the Amorites, who had fought against the former king of Moab, and taken all his land out of his hand, even to the Arnon" (Nu 21:26). The river marks the southern limit of that earlier Amorite seizure of Moabite land — and therefore the southern limit of the Sihon-kingdom Israel is about to fight.

Even Moab's own border-towns are named relative to this river. When Balak goes out to receive Balaam, he meets him "to Ar of Moab, which is on the border of the Arnon, which is in the utmost part of the border" (Nu 22:36). Ar sits on the edge of the Arnon, at the outermost reach of Moabite territory.

The Crossing into the Sihon Campaign

The Arnon is the line Israel is commanded to cross to begin the trans-Jordan conquest. The order is direct: "You⁺ rise up, take your⁺ journey, and pass over the valley of the Arnon: see, I have given into your hand Sihon the Amorite, king of Heshbon, and his land; begin to possess it, and contend with him in battle" (De 2:24). The pass-over of the Arnon valley and the hand-delivery of Sihon arrive in the same breath; the river is the threshold of the war.

The tally that follows the campaign measures the conquered land from the same anchor: "From Aroer, which is on the edge of the valley of the Arnon, and [from] the city that is in the valley, even to Gilead, there was not a city too high for us; Yahweh our God delivered up all before us" (De 2:36). Aroer, on the edge of the Arnon valley, is the southern starting-point of the count.

The same span is restated when Sihon and Og are taken together: "we took the land at that time out of the hand of the two kings of the Amorites who were beyond the Jordan, from the valley of the Arnon to mount Hermon" (De 3:8). The Arnon is the southern anchor; Hermon is the northern. Joshua's later list of struck kings repeats the survey verbatim: the sons of Israel "possessed their land beyond the Jordan toward the sunrising, from the valley of the Arnon to mount Hermon, and all the Arabah eastward" (Jos 12:1).

Tribal Allotment along the Arnon

When the conquered land is parceled to Reuben and Gad, the Arnon is again the southern boundary: "to the Reubenites and to the Gadites I gave from Gilead even to the valley of the Arnon, the middle of the valley, and the border [of it], and to the river Jabbok, which is the border of the sons of Ammon" (De 3:16). Two rivers frame the inheritance — the Arnon to the south, the Jabbok to the north as the Ammonite line.

Jephthah's Land-Claim

Generations later, the Arnon is still the line by which the trans-Jordan tract is measured. The Ammonite king sends a war-claim to Jephthah: "Because Israel took away my land, when he came up out of Egypt, from the Arnon even to the Jabbok, and to the Jordan: now therefore restore those [lands] again peacefully" (Jg 11:13). The Arnon is the southern edge of the disputed territory, the Jabbok the northern stretch, the Jordan the western limit.

The Book of the Wars

The Arnon is named in a fragment quoted from an older war-tradition: "Therefore it is said in the Book of the Wars of [the Speech of] Yahweh, Vaheb in Suphah, And the valleys of the Arnon," (Nu 21:14). The valleys of the Arnon belong to the cited text — the river is part of the geography commemorated in the older war-record.

The Fords of the Arnon

The Arnon's last appearance is a refugee scene. As Moab collapses, Isaiah pictures its women clustered at the river's crossing: "as wandering birds, as a scattered nest, so will the daughters of Moab be at the fords of the Arnon" (Isa 16:2). The same boundary-river that opened Moab's territory in Numbers becomes, in Isaiah, the edge at which the displaced gather.