Deuteronomy 2:1

Sea, encamping again at Mosera. When they were at Asiongaber, they were ordered to go to the north, by the mountains of Idumea or of Seir. Being arrived at Cades, they attempted to penetrate into Chanaan, by the road of the spies, but were repulsed. Upon which they asked leave of the Idumeans to pass through their country, lying south of the Dead Sea, but could not obtain permission, and God would not suffer them to force a passage, but ordered them to go round their territories, Numbers xx., and xxi. (Calmet)