He says that they had acted perfidiously with God, for they had violated his covenant. We must bear in mind what I have said before of the mutual faith which God stipulates with us, when he binds himself to us. God then covenants with us on this condition, that he will be our Father and Husband; but he requires from us such obedience as a son ought to render to his father; he requires from us that chastity which a wife owes to her husband. The Prophet now charges the people with unfaithfulness, because they had despised the true God, and prostituted themselves to idols. And he also aggravates this crime by saying, that they had begotten strange children: for he intimates, that their condition had become so vitiated, that there remained no better hope as to their posterity. Some explain the words, that they had begotten strange children, in this way, -- that they had taken wives from heathen nations, contrary to the law. But this sense is very frigid. Others understand, that they had begotten spurious children, because they brought up their children badly, having, from their infancy, attached them to depraved superstitions. This is indeed true, but the prophet, as I have already said, looked further; he meant that the Israelites had not only become alienated from God, but had also taken away every hope as to the future. It may indeed be, and it sometimes happens, that men for a time abandon themselves to many vices, and afterwards return to the right way; but when corruption has so prevailed that the children are infected with the same vices, and impiety itself takes full possession of them, then the state of things is past recovery. We now then see that the Prophet means, that the Israelites were not only covenant-breakers with respect to God, but that they had also led their children into the same perfidy, so that there was no hope of repentance. He therefore subjoins the punishment, Devour them shall a month together with their portions [1] Some restrict the word, month, to the times of the new moon, or to the new moons; and these days, we know, were festivals among the Jews: but this seems too far-fetched and strained. The Prophet therefore, I doubt not, takes here a month for a short time; and so the Hebrew scholars explain it, and yet they do not sufficiently unfold this form of speaking. Now, the Prophets are wont to use various figures, when they intend to mark out a short time. Isaiah says, Yet for three years, as the time of a hireling:' for hirelings were wont to hire themselves for three years; hence he says, This is the time fixed by the Lord as the appointed day. Contracts, also, we know, were then monthly, as they are at this day yearly, both with reference to the interest of money and other exchanges. Since, then, they usually made agreements for single months, the Prophet here, I have no doubt, takes a month metaphorically for a certain and fixed time. I do not therefore agree with the Hebrew scholars, who say that only a short time is expressed by the Prophet, but he expresses not only a short, but also a fixed time; and he did this that the Israelites might not vainly look for any deferring or respite, for hypocrites ever procrastinate and extend time by vain delusions. The Prophet therefore says here, A month shall devour them, which means, "Vengeance is now suspended over their heads, and this they shall not escape." And he says, "with their portions". He intimates here, no doubt, that though they then overflowed with abundance, yet nothing would be a help to them to keep them from being destroyed, for the hand of God was against them. We indeed know, that as long as men are well furnished with provisions and protection, they are not very solicitous about their state, but heedlessly despise whatever dangers there may be in the world: therefore the Prophet says, that though they were opulent and well supplied, though they possessed every kind of defense, yet nothing would avail for their safety, but a month should devour them, together with all their wealth. It follows --

Footnotes

1 - "With their portions," i.e., their allotments: they shall be totally dispossessed of their country; and the boundaries of the separate allotments of the several tribes shall be confounded and obliterated. --Bp. Horsley

They have dealt treacherously - Literally, "have cloaked," and so, acted deceitfully. The word is used of treachery of friend toward his friend, of the husband to his wife, or the wife husband. "Surely as a wife treacherously departeth from her husband, so have ye dealt treacherously with Me, O house of Israel, saith the Lord" Jeremiah 3:20. God, even in His upbraiding, speaks very tenderly to them, as having been in the closest, dearest relation to Himself.
For they have begotten strange children - God had made it a ground of the future blessing of Abraham, "I know him, that he will command his children and his household after him, and they shall keep the way of the Lord, to do justice and judgment" Genesis 18:19. But these, contrariwise, themselves being idolaters and estranged from God, had children, who fell away like themselves, strangers to God, and looked upon as strangers by Him. The children too of the forbidden marriages with the pagan were, by their birth, strange or foreign children, even before they became so in act; and they became so the more in act, because they were so by birth. The next generation then growing up more estranged from God than themselves, what hope of amendment was there?
Now shall a month devour - The word now denotes the nearness and suddenness of God's judgments; the term "month," their rapidity. A "month" is not only a brief time, but is almost visibly passing away; the moon, which measures it, is never at one stay, waxing until it is full, then waning until it disappears. Night by night bears witness to the month's decay. The iniquity was full; the harvest was ripe; "now," suddenly, rapidly, completely, the end should come. One month should "devour them with their portions." God willed to be the Portion of His people; He had said, "the Lord's portion is His people; Jacob is the lot of His inheritance" Deuteronomy 32:9. To Himself He had given the title, "the protion of Jacob" Jeremiah 10:16. Israel had chosen to himself "other portions" out of God, for these, he had forsaken his God; therefore he should be consumed with them. "All that they had, all that they possessed, enjoyed, trusted in, all, at once, shall that short space, suddenly and certainly to come; devour, deprive and bereave them of; none of them shall remain with them or profit them in the day of wrath."

Now shall a month devour them - In a month's time the king of Assyria shall be upon them, and oblige them to purchase their lives and liberties by a grievous tax of fifty shekels per head. This Menahem, king of Israel, gave to Pul, king of Assyria, 2-Kings 15:16-20. Instead of month, some translate the original locust. "The locusts shall devour them."

They have dealt treacherously against the LORD: for they have begotten (f) strange children: now shall (g) a month devour them with their portions.
(f) That is, their children are degenerate, so that there is no hope in them.
(g) Their destruction is not far off.

They have dealt treacherously against the Lord,.... Which was the reason of his departure from them; as a woman deals treacherously with her husband when she is unfaithful to him, and commits adultery; so Israel and Judah dealt treacherously with the Lord, who stood in the relation of a husband to them in covenant, by committing idolatry;
for they have begotten strange children; either of strange women, the daughters of idolatrous Heathens they married, so the Targum, Jarchi, and Kimchi; or rather their natural children, though born of Israelitish or Jewish parents, both such; yet being educated by them in an idolatrous way, and brought up in the commission of the evils their parents were guilty of, are said to be strange children to the Lord, alienated from him and his worship, and as such to be begotten:
now shall a month devour them with their portions; the Jews understand this literally of the month Ab, the time of Jerusalem's destruction, so Jarchi and R. Jeshuah in Aben Ezra and Ben Melech; or the month Tammuz, in which the city was broke up, and the month Ab, in which it was destroyed, as Kimchi; or rather, which is also a sense he mentions, it signifies a short time, a very little while before the destruction should come; and compares it with Zac 11:8; though, according to the Targum, it is to be understood of every month; and so denotes the continual desolation that should be made, until they were utterly destroyed; but others seem better to interpret it of their new moon, or first day of the month, which they observed in a religious way, by offering sacrifice, &c. and on which they depended; but this should be so far from being of any service to them, that it should turn against them; and, because of the idolatry committed in them, the Lord would hate them, and destroy them on account of them; even their farms, and fields, and vineyards, which were their portions and inheritances; see Isaiah 1:13; unless it is rather to be understood of the parts of the beasts slain in sacrifice on those days, to appease the Lord; which would be so far from doing it, that they would provoke him yet more to wrath, and slay them.

treacherously--as to the marriage covenant (Jeremiah 3:20).
strange children--alluding to "children of whoredoms" (Hosea 1:2; Hosea 2:4). "Strange" or foreign implies that their idolatry was imported from abroad [HENDERSON]. Or rather, "regarded by God as strangers, not His," as being reared in idolatry. The case is desperate, when not only the existing, but also the rising, generation is reared in apostasy.
a month--a very brief space of time shall elapse, and then punishment shall overtake them (Zac 11:8). The allusion seems to be to money loans, which were by the month, not as with us by the year. You cannot put it off; the time of your destruction is immediately and suddenly coming on you; just as the debtor must meet the creditor's demand at the expiration of the month. The prediction is of the invasion of Tiglath-pileser, who carried away Reuben, Gad, Naphtali, and the half tribe of Manasseh.
portions--that is, possessions. Their resources and garrisons will not avail to save them. HENDERSON explains from Isaiah 57:6, "portions" as their idols; the context favors this, "the Lord" the true "portion of His people" (Deuteronomy 32:9), being in antithesis to "their portions," the idols.

Have begotten - They have trained up their children in the same idolatry. A month - Possibly it may refer to Shallum's short time of usurpation, which lasted but a month; the Assyrians shall make a speedy conquest over you. With their portions - With all their substance.