Numbers 21:13
“From thence they removed, and pitched on the other side of Arnon, which is in the wilderness that cometh out of the coasts of the Amorites: for Arnon is the border of Moab, between Moab and the Amorites.”
And they journeyed from Oboth, and pitched at Ije–abarim, in the wilderness which is before Moab, toward the sunrising.
From thence they removed, and pitched in the valley of Zared.
From thence they removed, and pitched on the other side of Arnon, which is in the wilderness that cometh out of the coasts of the Amorites: for Arnon is the border of Moab, between Moab and the Amorites.
Wherefore it is said in the book of the wars of the Lord, What he did in the Red sea, and in the brooks of Arnon,
And at the stream of the brooks that goeth down to the dwelling of Ar, and lieth upon the border of Moab.
Counter-Arguments
The strongest case that this verse does not belong in this theme.
Cross-References
“Then they went along through the wilderness, and compassed the land of Edom, and the land of Moab, and came by the east side of the land of Moab, and pitched on the other side of Arnon, but came not within the border of Moab: for Arnon was the border of Moab.”
“And when Balak heard that Balaam was come, he went out to meet him unto a city of Moab, which is in the border of Arnon, which is in the utmost coast.”
“Rise ye up, take your journey, and pass over the river Arnon: behold, I have given into thine hand Sihon the Amorite, king of Heshbon, and his land: begin to possess it, and contend with him in battle.”
“For it shall be, that, as a wandering bird cast out of the nest, so the daughters of Moab shall be at the fords of Arnon.”
“Wherefore it is said in the book of the wars of the Lord, What he did in the Red sea, and in the brooks of Arnon,”