See commentary on Deuteronomy 2:19-37.

Deuteronomy 2:24-36

_ _ Rise ye up ... and pass over the river Arnon — At its mouth, this stream is eighty-two feet wide and four deep. It flows in a channel banked by perpendicular cliffs of sandstone. At the date of the Israelitish migration to the east of the Jordan, the whole of the fine country lying between the Arnon and the Jabbok including the mountainous tract of Gilead, had been seized by the Amorites, who, being one of the nations doomed to destruction (see Deuteronomy 7:2; Deuteronomy 20:16), were utterly exterminated. Their country fell by right of conquest into the hands of the Israelites. Moses, however, considering this doom as referring solely to the Amorite possessions west of Jordan, sent a pacific message to Sihon, requesting permission to go through his territories, which lay on the east of that river. It is always customary to send messengers before to prepare the way; but the rejection of Moses’ request by Sihon and his opposition to the advance of the Israelites (Numbers 21:23; Judges 11:26) drew down on himself and his Amorite subjects the predicted doom on the first pitched battlefield with the Canaanites. It secured to Israel not only the possession of a fine and pastoral country, but, what was of more importance to them, a free access to the Jordan on the east.