We have here an extract out of the genealogies,
I. Of the tribe of Reuben, where we have,
1. The reason why this tribe is thus postponed. It is confessed that Reuben was the first-born of Israel, and, upon that account, might challenge the precedency; but he forfeited his birthright by defiling his father's concubine, and was, for that, sentenced not to excel, Gen 49:4. Sin lessens men, thrusts them down from their excellency. Seventh-commandment sins especially leave an indelible stain upon men's names and families, a reproach which time will not wipe away. Reuben's seed, to the last, bear the disgrace of Reuben's sin. Yet, though that tribe was degraded, it was not discarded or disinherited. The sullying of the honour of an Israelite is not the losing of his happiness. Reuben loses his birthright, yet it does not devolve upon Simeon the next in order; for it was typical, and therefore must attend, not the course of nature, but the choice of grace. The advantages of the birthright were dominion and a double portion. Reuben having forfeited these, it was thought too much that both should be transferred to any one, and therefore they were divided. (1.) Joseph had the double portion; for two tribes descended from him, Ephraim and Manasseh, each of whom had a child's part (for so Jacob by faith blessed them, Heb 11:21; Gen 48:15, Gen 48:22), and each of those tribes was as considerable, and made as good a figure, as any one of the twelve, except Judah. But, (2.) Judah had the dominion; on him the dying patriarch entailed the sceptre, Gen 49:10 Of him came the chief ruler, David first, and, in the fulness of time, Messiah the Prince, Mic 5:2. This honour was secured to Judah, though the birthright was Joseph's; and, having this, he needed not envy Joseph the double portion.
2. The genealogy of the princes of this tribe, the chief family of it (many, no doubt, being omitted), to Beerah, who was head of this clan when the king of Assyria carried them captive, Ch1 5:4-6. Perhaps he is mentioned as prince of the Reubenites at that time because he did not do his part to prevent the captivity.
3. The enlargement of the coasts of this tribe. They increasing, and their cattle being multiplied, they crowded out their neighbours the Hagarites, and extended their conquests, though not to the river Euphrates, yet to the wilderness which abutted upon that river, Ch1 5:9, Ch1 5:10. Thus God did for his people as he promised them: he cast out the enemy from before them by little and little, and gave them their land as they had occasion for it, Exo 23:30.
II. Of the tribe of Gad. Some great families of that tribe are here named (Ch1 5:12), seven that were the children of Abihail, whose pedigree is carried upwards from the son to the father (Ch1 5:14, Ch1 5:15), as that Ch1 5:4, Ch1 5:5, is brought downwards from father to son. These genealogies were perfected in the days of Jotham king of Judah, but were begun some years before, in the reign of Jeroboam II, king of Israel. What particular reason there was for taking these accounts then does not appear; but it was just before they were carried away captive by the Assyrians, as appears Kg2 15:29, Kg2 15:31. When the judgments of God were ready to break out against them for their wretched degeneracy and apostasy then were they priding themselves in their genealogies, that they were the children of the covenant; as the Jews, in our Saviour's time, who, when they were ripe for ruin, boasted, We have Abraham to our father. Or there might be a special providence in it, and a favourable intimation that though they were, for the present, cast out, they were not cast off for ever. What we design to call for hereafter we keep an inventory of.

And they dwelt in their tents - The Hagarites were tribes of Nomade, or Scenite, Arabs; people who lived in tents, without any fixed dwellings, and whose property consisted in cattle. The descendants of Reuben extirpated these Hagarites, seized on their property and their tents, and dwelt in their place.

And the children of Gad dwelt over against them,.... Or by them, the Reubenites; and one part of Gilead was given them between them, and the other to the half tribe of Manasseh:

in the land of Bashan, unto Salcah; for though all Bashan is said to be given to the half tribe of Manasseh, Deu 3:13 yet that is to be understood of the greater part of it; all of that which belonged to Og, but what did not, the Gadites, either from the first, or in later times, inhabited even as far as Salcah, which was one of the cities of Og, Deu 3:10 and which Benjamin of Tudela (w) makes mention of, being called by the same name in his days.

(w) Itinerar. p. 57.

Eastward he inhabited unto the entering in of the wilderness from the river Euphrates--The settlement was on the east of Jordan, and the history of this tribe, which never took any part in the public affairs or movements of the nation, is comprised in "the multiplication of their cattle in the land of Gilead," in their wars with the Bedouin sons of Hagar, and in the simple labors of pastoral life. They had the right of pasture over an extensive mountain range--the great wilderness of Kedemoth (Deu 2:26) and the Euphrates being a security against their enemies.