Jamieson-Fausset-Brown Bible Commentary

Now rise up, and get you over the brook Zered--The southern border of Moab, Zered ("woody"), now Wady Ahsy, separates the modern district of Kerak from Jebal, and, indeed, forms a natural division of the country between the north and south. Ar, called in later times Rabbah, was the capital of Moab and situated twenty-five miles south of the Arnon on the banks of a small but shady stream, the Beni Hamed. It is here mentioned as representative of the country dependent on it, a rich and well-cultivated country, as appears from the numerous ruins of cities, as well as from the traces of tillage still visible on the fields.