Jamieson, Fausset and Brown on 1 Chronicles 5:18-22

18-22. Hagarites--or, "Hagarenes," originally synonymous with "Ishmaelites," but afterwards applied to a particular tribe of the Arabs (compare Psa 83:6).

Jetur--His descendants were called Itureans, and the country Auranitis, from Hauran, its chief city. These, who were skilled in archery, were invaded in the time of Joshua by a confederate army of the tribes of Reuben, Gad, and half Manasseh, who, probably incensed by the frequent raids of those marauding neighbors, took reprisals in men and cattle, dispossessed almost all of the original inhabitants, and colonized the district themselves. Divine Providence favoured, in a remarkable manner, the Hebrew army in this just war.