Therefore - More simply "and."

They are foolish - Or, they act foolishly (see Numbers 12:11), not having that knowledge which would enable them to guide their ways with discretion.

These are poor - They are ignorant; they have no education; they know no better.

Then I said, surely these are poor, they are foolish,.... The prophet, observing that reproofs and corrections in providence had no effect upon the people, he thought within himself that surely the reason must be, because these people are poor, and in low circumstances in the world, and are so busy in their worldly employments to get bread for their families, that they were not at leisure to attend unto divine things; nor of capacity to receive instruction and correction by providences; therefore it is they were so foolish, stupid, and infatuated:

for they know not the way of the Lord, nor the judgment of their God; either the way which God takes in the salvation of the sons of men, and in justifying of them, which is revealed in his word; or that which he prescribes them to walk in, in his law, even the way of truth and righteousness, and for failure of which he judges and condemns them; but of these things they were ignorant; see John 7:48, not that this is observed in excuse for them, but in order to introduce what follows; and to show that this depravity, stupidity, and ignorance, obtained among all sort of people, high and low, rich and poor.

This total want of good faith and uprightness is found not only in the lower orders of the populace, amongst the mean and ignorant rabble, but in the higher ranks of the educated. This is rhetorically put in this shape, that Jeremiah, believing that only the common people are so deeply sunk in immorality, turns to the great to speak to them, and amongst them discovers a thorough-going renunciation of the law of God. דּלּים, weak, are the mean and poor of the people, who live from hand to mouth in rudeness and ignorance, their anxieties bent on food and clothing (cf. Jeremiah 39:10; Jeremiah 40:7). These do foolishly (נואלוּ as in Numbers 12:11), from want of religious training. They know not the way of Jahveh, i.e., the way, the manner of life, prescribed to men by God in His word; cf. 2 Kings 21:22; Psalm 25:9, etc. The judgment of their God, i.e., that which God demanded as right and lawful, 2 Kings 17:26, etc. The great, i.e., the wealthy, distinguished, and educated. Yet even these have broken the yoke of the law, i.e., have emancipated themselves from obedience to the law (Hitz.); cf. Jeremiah 2:20. Therefore they must be visited with punishment.

Therefore I said, Surely these are poor; they are foolish: for they know not the way of the LORD, nor the judgment of their God.

5:4 Poor - The vulgar, that understand but little, of less conscience than the better sort. Judgment - The methods or ways of his providence.

4. poor-rather, "the poor." He supposes for the moment that this utter depravity is confined to the uninstructed poor, and that he would find a different state of things in the higher ranks: but there he finds unbridled profligacy.

5:1-9 None could be found who behaved as upright and godly men. But the Lord saw the true character of the people through all their disguises. The poor were ignorant, and therefore they were wicked. What can be expected but works of darkness, from people that know nothing of God and religion? There are God's poor, who, notwithstanding poverty, know the way of the Lord, walk in it, and do their duty; but these were willingly ignorant, and their ignorance would not be their excuse. The rich were insolent and haughty, and the abuse of God's favours made their sin worse.