That which the palmerworm hath left - Here he begins to open his message, and the words he chooses show that he is going to announce a devastation of the land by locusts, and a famine consequent on their depredations. What the different insects may be which he specifies is not easy to determine. I shall give the words of the original, with their etymology.
The palmerworm, גזם gazam, from the same root, to cut short; probably the caterpillar, or some such blight, from its cutting the leaves of the trees into pieces for its nourishment.
The locust, ארבה arbeh, from רבה rabah, to multiply, from the immense increase and multitude of this insect.
Cankerworm, ילק yelek, from לק lak, to lick or lap with the tongue; the reference is uncertain.
Caterpillar, חסיל chasil, from חסל chasal, to consume, to eat up, the consumer. Bishop Newcome translates the first grasshopper; the second, locust; the third, devouring locust; and the fourth, consuming locust. After all that has been said by interpreters concerning these four animals, I am fully of opinion that the arbeh, or locust himself, is the gazam, the yelek, and the chasil and that these different names are used here by the prophet to point out the locust in its different states, or progress from embryo to full growth. See the note on Joel 2:2; (note).
That which the palmerworm hath left, hath the locust eaten - The creatures here spoken of are different kinds of locusts, so named from their number or voracity. We, who are free from this scourge of God, know them only by the generic name of locusts. But the law mentions several sorts of locusts, each after its kind, which might be eaten. In fact, above eighty different kinds of locusts have been observed, some of which are twice as large as that which is the ordinary scourge of God. Slight as they are in themselves, they are mighty in God‘s Hand; beautiful and gorgeous as they are, floating in the sun‘s rays, they are a scourge, including other plagues, famine, and often, pestilence.
Of the four kinds, here named by the prophet, that rendered “locust” is so called from its multitude, (from where Jeremiah says “they are more numerous than the locust” See Judges 6:5; Judges 7:12; Psalm 105:34; Nahum 3:15. It is a proverb in Arabic also)), and is, probably, the creature which desolates whole regions of Asia and Africa. The rest are named from their voracity, the “gnawer,” “licker,” “consumer,” but they are, beyond doubt, distinct kinds of that destroyer. And this is the characteristic of the prophet‘s threatening, that he foretells a succession of destroyers, each more fatal than the preceding; and that, not according to the order of nature. For in all the observations which have been made of the locusts, even when successive flights have desolated the same land, they have always been successive clouds of the same creature.
Over and above the fact, then, that locusts are a heavy chastisement from God, these words of Joel form a sort of sacred proverb. They are the epitome of his whole prophecy. It is “this” which he had called the old men to hear, and to say whether they had known anything like “this;” that scourge came after scourge, judgment after judgment, until man yielded or perished. The visitation of locusts was one of the punishments threatened in the law, “Thou shall carry much seed out into the field, and shalt gather but little in, for the locust shall consume it” Deuteronomy 28:38. It was one of God‘s ordinary punishments for sin, in that country, like famine, or pestilence, or blight, or mildew, or murrain, or (in this) potato disease. Solomon, accordingly, at the dedication of the temple mentions the locust among the other plagues, which he then solemnly entreated God to remove, when individuals or the whole people should spread forth their hands in penitence toward that house 1 Kings 8:37-38.
But the characteristic of “this” prophecy is the successiveness of the judgments, each in itself, desolating, and the later following quick upon the earlier, and completing their destructiveness. The judgments of God are linked together by an invisible chain, each drawing on the other; yet, at each link of the lengthening chain, allowing space and time for repentance to break it through. So in the plagues of Egypt, God, “executing His judgments upon them by little and little, gave them time for repentance” (Wisd. 12:10); yet, when Pharaoh hardened his heart, each followed on the other, until he perished in the Red Sea. In like way God said, “him that escapeth the sword of Hazael shall Jehu slay; and him that escapeth from the sword of Jehu shall Elisha slay” 1 Kings 19:17. So, in the Revelation, the “trumpets” are sounded Revelation 8:1-13; Revelation 11:15, and “the vials of the wrath of God are poured out upon the earth, one after the other” Revelation 16. Actual locusts were very likely one of the scourges intended by the prophet. They certainly were not the whole; but pictured others fiercer, more desolating, more overwhelming. The proverbial dress gained and fixed people‘s attention on the truth, which, if it had been presented to the people nakedly, they might have turned from. Yet as, in God‘s wisdom, what is said generally, is often fulfilled specially, so here there were four great invaders which in succession wasted Judah; the Assyrian, Chaldaean, Macedonian and Roman.
Morally, also, four chief passions desolate successively the human heart.: “For what is designated by the “palmerworm,” which creeps with all its body on the ground, except it be lust, which so pollutes the heart which it possesses, that it cannot rise up to the love of heavenly purity? What is expressed by the “locust,” which flies by leaps, except vain glory which exalts itself with empty presumptions? What is typified by the “cankerworm,” almost the whole of whose body is gathered into its belly, except gluttony in eating? What but anger is indicated by mildew, which burns as it touches? What the “palmerworm” then “hath left the locust heath eaten,” because, when the sin of lust has retired from the mind, vain glory often succeeds. For since it is not now subdued by the love of the flesh, it boasts of itself, as if it were holy through its chastity. “And that which the locust hath left, the cankerworm hath eaten,” because when vain glory, which came, as it were, from holiness, is resisted, either the appetite, or some ambitious desires are indulged in too immoderately. For the mind which knows not God, is led the more fiercely to any object of ambition, in proportion as it is not restrained by any love of human praise. “That which the cankerworm hath left,” the mildew consumes, because when the gluttony of the belly is restrained by abstinence, the impatience of anger holds fiercer sway, which, like mildew, eats up the harvest by burning it, because the flame of impatience withers the fruit of virtue. When then some vices succeed to others, one plague devours the field of the mind, while another leaves it.”