1 Judah and Joseph preferred before Reuben, who forfeited his birthright.
3 Ruben's descendants; some of whom vanquish the Hagarites. 11 The chief men of Gad, and their habitations. 18 Ruben, Gad, and half of Manasseh, obtain a victory over the Hagarites. 23 The habitations and chief men of that half of Manasseh. 25 The captivity of the two tribes and half, for their sins. (OLB, Treasury of Scriptural Knowledge.)
Vv. 1-3, Ruben, the firstborn, lay with one of his father's wives, so he lost the birthright, which consisted of a double portion of what the father might leave, and the spiritual leadership of the family "clan" that is, the blessing. Everything passed over him because of his sin. Though Judah sinned with his daughter-in-law, he readily faced up to it when confronted, and he obtained the blessing. Joseph was exalted by God, and kept his family alive. Jacob gave him the double portion by splitting Joseph's "tribe" in two, Manasseh and Epherem.
V. 19, war with the Hagarites, or the "Ishmaelites". These were and are the Arabs.
I. In a glorious victory over the Hagarites, so the Ishmaelites were now called, to remind them that they were the sons of the bond-woman, that was cast out. We are not told when this victory was obtained: whether it be the same with that of the Reubenites (which is said #1Ch 5:10 to be in the days of Saul), or whether that success of one of these tribes animated and excited the other two to join with them in another expedition, is not certain. It seems, though in Saul's time the common interests of the kingdom were weak and low, some of the tribes that acted separately did well for themselves. (MH)
V. 20, it appears that the battle went against them, so they cried out to the Lord. However, it could be that they cried out at the first. Regardless, acting as true people of God, they called upon their God for His aid in the battle.
V. 21, there were only 44,730 men of Israel who went to battle, yet they captured alive 100,000 Hagarites, or Arabs.
V. 22, there were a great many Arabs slain, because the battle was of the Lord.
V. 25, though they had great success and prospered greatly in the land, their decedents departed from the God of their prosperity, and served the false gods around them.
We can say, How could they do that? Answer Just look around us at how the children of the founders of America have departed from the God of our prosperity, and are now serving the false God's around us.
I believe it starts by fathers failing to teach their children the ways of the Lord.
V. 26, the God of Israel stirred up the spirit of their enemy, and delivered them into his hands.
II. They shared, at length, in an inglorious captivity. Had they kept close to God and their duty, they would have continued to enjoy both their ancient lot and their new conquests; but they transgressed against the God of their fathers, #1Ch 5:25. They lay upon the borders, and conversed most with the neighbouring nations, by which means they learned their idolatrous usages and transmitted the infection to the other tribes; for this God had a controversy with them. He was a husband to them, and no marvel that his jealousy burnt like fire when they went a whoring after other gods. Justly is a bill of divorce given to the adulteress. God stirred up the spirit of the kings of Assyria, first one and then another, against them, served his own purposes by the designs of those ambitious monarchs, employed them to chastise these revolters first, and, when that humbled them not, then wholly to root them out, #1Ch 5:26. These tribes were first placed, and they were first displaced. They would have the best land, not considering that it lay most exposed. But those who are governed more by sense than by reason or faith in their choices may expect to fare accordingly. (MH)
(l) Thus God stirred up the wicked and used them as instruments to execute his just judgment against sinners, although they were led by malice and ambition. (Geneva)
Throughout the Scripture, God uses the wicked as instruments to judge His people. Can we expect anything less from Him today?