This country, that was excluded, was something barren. The Talmudists speak thus of it; "That tract, which lies in Gerariku [Gerar] is ill to dwell in. How far? To the river of Egypt." And Strabo thus; "The country, which follows Gaza, is barren and sandy," &c.
It was anciently inhabited by the Avites, -- namely, from Gaza to the river of Egypt. "The Avims dwelt in Hazerim," Deuteronomy 2:23. Hazar is a word of most frequent mention in that southern land, "Hazar-Addar, Hazar-Gaddah, Hazar-Shua, Hazar-Susah," &c. And it seems to denote some champaign plain and level, lying between the mountains. Hence the habitation of the Avites is called 'Hazerim'; who are numbered with the Philistines, but yet by themselves, Joshua 13:3: -- for see there, how the holy text promising to number five nations only, numbers six.
This excluded portion is passed into the name of Idumea. Hence Pliny: "Presently from the rising up of the lake Sirbon, begins Idumea and Palestine." Nor that alone, but another very great part of Judea. Hence the sea of Sodom, is said, by Diodorus Siculus, to be "about the middle of Idumea." And in Josephus, and the Book of the Maccabees, we find very many places mentioned under the name of Idumea, which were almost in the very middle of Judea. For example's sake; "He came even to the Gadari, and the plains of Idumea, and Azotus, and Jamnia." And again; "And Judas and his brethren left not off fighting with the Idumeans: but fell upon them everywhere: and taking the city Chebron, &c. and the city Marissa, &c. And having come unto Azotus," &c. And more to this purpose may be read here and there. So that distinction may be made, between Idumea the Greater and the Less. Simon of Gerasa overran the towns along the mountainous country, &c. And he overran Acrabatene, and the parts as far as Idumea the Great. And there is mention of "Idumean, called the Upper." With these passages, compare Mark 3:8.
Whilst the Jews were absent from their own country, enduring the seventy years' bondage in Babylon, -- it is easy to be believed, that their ancient enemies, the Edomites, and that were so from the very first original of them, had invaded their possessions, as much as they could, and had fixed their roots in that country especially, which was nearest their own: but at length, by the powerful arms of the Maccabees, and the Asmoneans, they were either rooted out, or constrained to embrace Judaism. So Josephus speaks of Hyrcanus: "Hyrcanus takes Ador and Marissa, cities of Idumea: and, having subdued all the Idumeans, suffered them to remain in the country, on condition they were willing to be circumcised, and to use the Jewish laws. And they, out of a desire of their own country, underwent circumcision, and conformed to the same course of life with the Jews." Hence there became a mingled generation in that country, between Jew and Edomite: and the name of the place was mingled also, and called both Idumea and Judea: "And Palestine was divided into five countries, -- Idumea, Judea, Samaria, Galilee, and the country beyond Jordan."