Look, here come the armies of Ammon, Moab, and Mount Seir, those very countries you did not let Israel invade when they came out of Egypt. Israel left them alone and did not destroy them.
But Sihon refused to allow the Israelites to travel through his territory. Instead, he called out his whole army and went out to meet the Israelites head-on in the desert. When he arrived at Jahaz, he attacked the Israelites.
The Israelites left Mount Hor by the road leading to the Red Sea so they could avoid traveling through the country of Edom. But the people became bad-tempered on the way
just like the descendants of Esau living in Seir and the Moabites living in Ar allowed us, until we cross over the Jordan into the country that the Lord our God is giving to us.”
They sent messengers to the king of Edom, saying, ‘Please let us pass through your country,’ but the king of Edom refused to listen. They also sent the same request to the king of Moab, and he refused too. So they remained at Kadesh.
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.