Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
His birthright was given ... - In particular, the right of the first-born to a double inheritance Deu 21:17 was conferred on Joseph, both by the expressed will of Jacob Gen 48:22 and in the actual partition of Canaan Josh. 16-17. But though the birthright, as respecting its material privileges, passed to Joseph, its other rights, those of dignity and pre-eminence, fell to Judah; of whom came the chief ruler, an allusion especially to David, though it may reach further, and include a glance at the Messiah, the true "Ruler" of Israel Mic 5:2.
The sons of Joel - The line of succession here given must be broken by one great gap or several smaller ones, since nine generations before Tiglath-pileser would carry us back no further than the reign of Rehoboam.
He inhabited - i. e. Reuben. Eastward the Reubenites inhabited as far as the commencement of the great Syrian Desert, which extended all the way from the river Euphrates to their borders.
The "Hagarites" or "Hagarenes" are generally regarded as descendants of Hagar, and a distinct branch of the Ishmaelites Ch1 27:30-31; Psa 83:6. They appear to have been one of the most wealthy Ch1 5:21 and widely-spread tribes of the Syrian Desert, being found on the side of the Euphrates in contact with the Assyrians, and also in the Hauran, in the neighborhood of Palestine, in contact with the Moabites and Israelites. If identical with the Agraei of the Classical writers, their name may be considered as still surviving in that of the district called Hejer or Hejera in northeastern Arabia, on the borders of the Persian Gulf. A full account of the war is given in Ch1 5:18-22.
From this passage and from the subsequent account of the Manassites Ch1 5:23-24, the Gadites extended themselves to the north at the expense of their brethren, gradually occupying a considerable portion of the tract originally allotted to the "half tribe."
The writer refers here to two registrations, one made under the authority of Jeroboam II when he was king and Israel flourishing, the other made under the authority of Jotham, king of Judah, during the troublous time which followed on the great invasion of Tiglath-pileser. There is nothing surprising in a king of Judah having exercised a species of lordship over the trans-Jordanic territory at this period.
Jetur no doubt gave his name to the important tribe of the Ituraeans who inhabited the region southwest of the Damascene plain, between Gaulonitis (Jaulan) and the Ledjah. This tribe was noted for its thievish habits, and was regarded as savage and warlike.
"Baal-Hermon," "Senir" Deu 3:9, and "Mount Hermon," are here not so much three names of the one great snow-clad eminence in which the Anti-Lebanon terminates toward the south, as three parts of the mountain - perhaps the "three summits" in which it terminates.
"Habor" here seems to be a city or a district, and not a river, as in marginal reference There is some reason to believe that districts among the Assyrians were occasionally named from streams.
Hara is probably the same as "Haran" Gen 11:31; Kg2 19:12; Eze 27:23, being a softening down of the rugged original "Kharan."