Numbers 21:4 - Albert Barnes' Notes on the Bible

The direct route to Moab through the valleys of Edom being closed against them Numbers 20:20-21, they were compelled to turn southward. Their course lay down the Arabah; until, a few hours north of Akaba (Ezion-Geber) the Wady Ithm opened to them a gap in the hostile mountains, allowed them to turn to their left, and to march northward toward Moab Deuteronomy 2:3. They were thus for some days (see Numbers 22:1 note) in the Arabah, a mountain plain of loose sand, gravel, and detritus of granite, which though sprinkled with low shrubs, especially near the mouths of the wadys and the courses of the winter-torrents, furnishes extremely little food or water, and is often troubled by sand-storms from the shore of the gulf. Hence, “the soul of the people was much discouraged because of the way.”