Jamieson, Fausset and Brown on 1 Chronicles 1:37

37. Reuel--a powerful branch of the great Aeneze tribe, the Rowalla Arabs.

Shammah--the great tribe Beni Shammar. In the same way, the names of the other kings and dukes are traced in the modern tribes of Arabia. But it is unnecessary to mention any more of these obscure nomads, except to notice that Jobab (1Ch 1:44), one of the kings of Edom, is considered to be Job, and that his seat was in the royal city of Dinahab (Ge 36:32; 1Ch 1:43), identified with O'Daeb, a well-known town in the center of Al Dahna, a great northern desert in the direction of Chaldea and the Euphrates [Forster].