The prophet here turns his speech, in God's name, to the men of the place where he lived. We have heard what words he proclaimed towards the north (Jer 3:12), for the comfort of those that were now in captivity and were humbled under the hand of God; let us now see what he says to the men of Judah and Jerusalem, who were now in prosperity, for their conviction and awakening. In these two verses he exhorts them to repentance and reformation, as the only way left them to prevent the desolating judgments that were ready to break in upon them. Observe,

I.The duties required of them, which they are concerned to do.

1.They must do by their hearts as they do by their ground that they expect any good of; they must plough it up (Jer 4:3): "Break up your fallow-ground. Plough to yourselves a ploughing (or plough up your plough land), that you sow not among thorns, that you may not labour in vain, for your own safety and welfare, as those do that sow good seed among thorns and as you have been doing a great while. Put yourselves into a frame fit to receive mercy from God, and put away all that which keeps it from you, and then you may expect to receive mercy and to prosper in your endeavours to help yourselves." Note, (1.) An unconvinced unhumbled heart is like fallow-ground, ground untilled, unoccupied. It is ground capable of improvement; it is our ground, let out to us, and we must be accountable for it; but it is fallow; it is unfenced and lies common; it is unfruitful and of no advantage to the owner, and (which is principally intended) it is overgrown with thorns and weeds, which are the natural product of the corrupt heart; and, if it be not renewed with grace, rain and sunshine are lost upon it, Heb 6:7, Heb 6:8. (2.) We are concerned to get this fallow-ground ploughed up. We must search into our own hearts, let the word of God divide (as the plough does) between the joints and the marrow, Heb 4:12. We must rend our hearts, Joe 2:13. We must pluck up by the roots those corruptions which, as thorns, choke both our endeavours and our expectations, Hos 10:12.

2.They must do that to their souls which was done to their bodies when they were taken into covenant with God (Jer 4:4): "Circumcise yourselves to the Lord, and take away the foreskin of your heart. Mortify the flesh and the lusts of it. Pare off that superfluity of naughtiness which hinders your receiving with meekness the engrafted word, Jam 1:21. Boast not of, and rest not in, the circumcision of the body, for that is but a sign, and will not serve without the thing signified. It is a dedicating sign. Do that in sincerity which was done in profession by your circumcision; devote and consecrate yourselves unto the Lord, to be to him a peculiar people. Circumcision is an obligation to keep the law; lay yourselves afresh under that obligation. It is a seal of the righteousness of faith; lay hold then of that righteousness, and so circumcise yourselves to the Lord."

II.The danger they are threatened with, which they are concerned to avoid. Repent and reform, lest my fury come forth like fire, which it is now ready to do, as that fire which came forth from the Lord and consumed the sacrifices, and which was always kept burning upon the altar and none might quench it; such is God's wrath against impenitent sinners, because of the evil of their doings. Note, 1. That which is to be dreaded by us more than any thing else is the wrath of God; for that is the spring and bitterness of all present miseries and will be the quintessence and perfection of everlasting misery. 2. It is the evil of our doings that kindles the fire of God's wrath against us. 3. The consideration of the imminent danger we are in of falling and perishing under this wrath should awaken us with all possible care to sanctify ourselves to God's glory and to see to it that we be sanctified by his grace.

For thus saith the Lord to the men of Judah and Jerusalem,.... The two tribes of Judah and Benjamin, who were at the time of this prophecy in their own land; and so are distinguished from Israel the ten tribes, who were in captivity; unless the same persons should be meant, who were called by these several names, the people of the Jews; and it was in Judea that our Lord appeared in the flesh, and to the inhabitants thereof he ministered, he was the minister of the circumcision; and so to the inhabitants of Jerusalem, whom he called to repentance, and would have gathered, Mat 23:37,

break up your fallow ground; this is ground that lies untilled, not ploughed, nor sown, on which nothing grows but the produce of nature, as weeds, thorns, briers, &c. is common to men and beasts, and is trodden upon, and, so is hard and unsusceptible of seed; which, if it accidentally falls upon it, makes no impression on it, and is not received by it; and the breaking of it up is by the plough. The "fallow ground" fitly represents the hearts of unregenerate men, which are unopened to the word, and unbroken by it; nor have they the seed of divine grace sown in them; but are destitute of faith, hope, love, fear, and the like; there is nothing grows there but the weeds of sin and corruption; and are like a common beaten road; are the common track of sin, where lusts pass to and fro, and dwell; and so are hardened and obdurate, as hard as a stone, yea, harder than the nether millstone; and who, though they may occasionally be under the word, it makes no impression on them; it has no place in them, but is like the seed that falls by the wayside, Mat 13:4, unless divine power attends it; for the Gospel is the plough, and ministers are the ploughmen; but it is the Lord alone that makes it effectual to the breaking up the fallow ground of men's hearts, Luk 9:62, but when the Lord puts his hand to the plough it enters within, and opens the heart; it is quick, powerful, and sharp; it cuts deep, and makes long and large furrows, even strong convictions of sin; it throws a man's inside outward, as the plough does the earth; and lays all the wicked of his heart open to him; and roots up the pride, the vanity, and boasting of the creature, and other lusts; and so makes way for the seed of divine grace to be sown there:

and sow not among thorns; or, "that ye may not sow among thorns" (o); for, unless the fallow ground is broken up, it will be no other than sowing among thorns; and unless the hearts of men are opened by the power and grace of God, they will not attend to the things that are spoken; preaching and eating the word will be like sowing among thorns; cares of this world, the deceitfulness of riches, the pleasures of life, and the lusts thereof, which are comparable to thorns, because pricking, perplexing, and distressing, and because vain and unprofitable, choke the word, and make it unfruitful; see Mat 13:7, now this exhortation in the text does not suppose power in man to break up and open his heart; but to show his want of renewing grace; the necessity of it; and the danger he is in without it; and to awaken in him a concern for it; see Eze 18:31. The words may be applied to backsliding professors, since backsliding Israel and Judah are the persons addressed; and this may be done with great propriety and pertinence to the simile; for fallow ground is that which has been broke up and sown, and laid fallow. It is usual to till and sow two years, and lay fallow a third: and backsliding Christians look very much like fallow ground; so faithless, so lukewarm, and indifferent; so inattentive to the word, and unconcerned under it; so barren and unfruitful, as if they had never had any faith, or love, or good work in them; so that they need to be renewed in the spirit of their minds; to have a new face of things put upon them: and to have a clean heart, and a right spirit, created in them. The Targum is,

"make to yourselves good works, and seek not salvation in sins.''

(o) "ut non seratis".

Transition to Judah. Supply mentally. All which (the foregoing declaration as to Israel) applies to Judah.

and Jerusalem--that is, and especially the men of Jerusalem, as being the most prominent in Judea.

Break . . . fallow ground--that is, Repent of your idolatry, and so be prepared to serve the Lord in truth (Hos 10:12; Mat 13:7). The unhumbled heart is like ground which may be improved, being let out to us for that purpose, but which is as yet fallow, overgrown with weeds, its natural product.