Then they moved on from there and camped on the far side of the Arnon River, in the desert near Amorite territory. The Arnon River is the border between the Moab and the Amorites.
When Balak found out that Balaam was on his way, he went out to meet him at the Moabite town on the border at the Arnon River, the farthest point of his territory.
Then the Lord told us, “Get up, go and cross the Arnon Valley. Look, I have handed over to you Sihon the Amorite, king of Heshbon, as well as his land. Go and start taking it over, and fight him in battle.
Eventually the Israelites traveled through the desert, avoiding the lands of Edom and Moab. They arrived on the east side of the land of Moab and camped on the other side of the Arnon River. But they did not enter Moab territory, for the Arnon River was its border.