Therefore thus says the Lord, the God of hosts: Because they have spoken this word, I am now making my words in your mouth a fire, and this people wood, and the fire shall devour them. I am going to bring upon you a nation from far away, O house of Israel, says the Lord. It is an enduring nation, it is an ancient nation, a nation whose language you do not know, nor can you understand what they say. Their quiver is like an open tomb; all of them are mighty warriors (NRSV 5:14-16).
Wherefore thus saith the Lord God of hosts, Because ye speak this word, behold, I will make my words in thy mouth fire, and this people wood, and it shall devour them. Lo, I will bring a nation upon you from far, O house of Israel, saith the Lord: it is a mighty nation, it is an ancient nation, a nation whose language thou knowest not, neither understandest what they say. Their quiver is as an open sepulchre, they are all mighty men (KJV 5:14-16).
Since the Judeans have been worshipping foreign gods, instead of their own God, they lose the right to be ruled by that God. They're punished by receiving the thing they seemingly wanted—getting ruled by a really hostile foreign nation. Be careful what you pray for and all that.
You will be in the right, O Lord, when I lay charges against you; but let me put my case to you. Why does the way of the guilty prosper? Why do all who are treacherous thrive? You plant them, and they take root; they grow and bring forth fruit; you are near in their mouths yet far from their hearts. But you, O Lord, know me; You see me and test me—my heart is with you. Pull them out like sheep for the slaughter, and set them apart for the day of slaughter. How long will the land mourn, and the grass of every field wither? For the wickedness of those who live in it the animals and the birds are swept away, and because people said, "He is blind to our ways." (NRSV 12:1-4)
Righteous art thou, O Lord, when I plead with thee: yet let me talk with thee of thy judgments: Wherefore doth the way of the wicked prosper? wherefore are all they happy that deal very treacherously? Thou hast planted them, yea, they have taken root: they grow, yea, they bring forth fruit: thou art near in their mouth, and far from their reins. But thou, O Lord, knowest me: thou hast seen me, and tried mine heart toward thee: pull them out like sheep for the slaughter, and prepare them for the day of slaughter. How long shall the land mourn, and the herbs of every field wither, for the wickedness of them that dwell therein? the beasts are consumed, and the birds; because they said, "He shall not see our last end." (KJV 12:1-4)
Jeremiah knows that whatever God plans is right, and there's ultimately no arguing with him. But he still asks him some searching questions, despite all that. Why do good things happen to bad people? Jeremiah seems to feel that his own righteousness gives him the cred to plead with God for the destruction of the wicked.
The heart is devious above all else; it is perverse—who can understand it? I the Lord test the mind and search the heart, to give to all according to their ways, according to the fruit of their doings. Like the partridge hatching what it did not lay, so are all who amass wealth unjustly; in mid-life it will leave them, and at their end they will prove to be fools (NRSV 17:9-11).
The heart is deceitful above all things, and desperately wicked: who can know it? I the Lord search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings. As the partridge sitteth on eggs, and hatcheth them not; so he that getteth riches, and not by right, shall leave them in the midst of his days, and at his end shall be a fool (KJV 17:9-11).
According to God, people who make unjust gains end up seeing those gains depart. It's a karmic thing. God seems to understand that humans are often motivated by emotion instead of reason, and this gets them into trouble.
Come, go down to the potter's house, and there I will let you hear my words. So I went down to the potter's house, and there he was working at his wheel. The vessel he was making of clay was spoiled in the potter's hand, and he reworked it into another vessel, as seemed good to him. Then the word of the Lord came to me: Can I not do with you, O house of Israel, just as this potter has done? says the Lord. Just like the clay in the potter's hand, so are you in my hand, O house of Israel (NRSV 18:2-6).
Arise, and go down to the potter's house, and there I will cause thee to hear my words. Then I went down to the potter's house, and, behold, he wrought a work on the wheels. And the vessel that he made of clay was marred in the hand of the potter: so he made it again another vessel, as seemed good to the potter to make it. Then the word of the Lord came to me, saying, O house of Israel, cannot I do with you as this potter? saith the Lord. Behold, as the clay is in the potter's hand, so are ye in mine hand, O house of Israel (KJV 18:2-6).
God indicates that his wrath and vengeful justice have their creative aspect, as well. They're forces that are helping shape Israel into the nation he wants it to be. Don't forgetteth, though, that this involves destruction. You have to get rid of the bad vessel before you start working on Israel 2.0.
In those days they shall no longer say: "The parents have eaten sour grapes, and the children's teeth are set on edge." But all shall die for their own sins; the teeth of everyone who eats sour grapes shall be set on edge (NRSV 31:29-30).
In those days they shall say no more, The fathers have eaten a sour grape, and the children's teeth are set on edge. But everyone shall die for his own iniquity: every man that eateth the sour grape, his teeth shall be set on edge (KJV 31:29-30).
The proverb cited here was a way of saying that successive generations are affected by the behaviors of the ones before them. In the early days of the nation, God often said that the sins of the fathers would affect the children to the third and fourth generation, and the same principle held for good behavior—the descendants would be rewarded. So this is a serious change. God now says that everyone's responsible for his own good and bad behavior and only they bear the consequences. That's important going forward, because Judah's just been destroyed because of its sins. In order to have any hope of better days ahead, the next generation needs to believe that they won't be punished for the older generation's disobedience. It's a whole new idea of justice.
Thus says the Lord: Do not deceive yourselves, saying, The Chaldeans will surely go away from us, for they will not go away. Even if you defeated the whole army of Chaldeans who are fighting against you, and there remained of them only wounded men in their tents, they would rise up and burn this city with fire (NRSV 37:9-10).
Thus saith the Lord; Deceive not yourselves, saying, The Chaldeans shall surely depart from us: for they shall not depart. For though ye had smitten the whole army of the Chaldeans that fight against you, and there remained but wounded men among them, yet should they rise up every man in his tent, and burn this city with fire (KJV 37:9-10).
God's justice is so absolute that no human plan can override it, even if the tide of events seems to turn in the total opposite direction.
But if you continue to say, "We will not stay in this land," thus disobeying the voice of the Lord your God and saying, "No, we will go to the land of Egypt, where we shall not see war, or hear the sound of the trumpet, or be hungry for bread, and there we will stay," then hear the word of the Lord, O remnant of Judah. Thus says the Lord of hosts, the God of Israel: If you are determined to enter Egypt and go to settle there, then the sword that you fear shall overtake you there, in the land of Egypt; and the famine that you dread shall follow close after you into Egypt; and there you shall die. All the people who have determined to go to Egypt to settle there shall die by the sword, by famine, and by pestilence; they shall have no remnant or survivor from the disaster that I am bringing upon them (NRSV 42:13-17).
But if ye say, We will not dwell in this land, neither obey the voice of the Lord your God, Saying, No; but we will go into the land of Egypt, where we shall see no war, nor hear the sound of the trumpet, nor have hunger of bread; and there will we dwell: And now therefore hear the word of the Lord, ye remnant of Judah; Thus saith the Lord of hosts, the God of Israel; If ye wholly set your faces to enter into Egypt, and go to sojourn there; Then it shall come to pass, that the sword, which ye feared, shall overtake you there in the land of Egypt, and the famine, whereof ye were afraid, shall follow close after you there in Egypt; and there ye shall die. So shall it be with all the men that set their faces to go into Egypt to sojourn there; they shall die by the sword, by the famine, and by the pestilence: and none of them shall remain or escape from the evil that I will bring upon them (KJV 42:13-17).
God clearly spells out the consequences for disobeying him beforehand. This does nothing to deter anybody. People are swayed more by what they see in front of them in Judah—no food, war, enslavement, a destroyed city—than by some predicted future fate in Egypt. That's a pretty accurate description of human nature.
Declare among the nations and proclaim, set up a banner and proclaim, do not conceal it, say: Babylon is taken, Bel is put to shame, Merodach is dismayed. Her images are put to shame, her idols are dismayed. For out of the north a nation has come up against her; it shall make her land a desolation, and no one shall live in it; both human beings and animals shall flee away. In those days and in that time, says the Lord, the people of Israel shall come, they and the people of Judah together; they shall come weeping as they seek the Lord their God. They shall ask the way to Zion, with faces turned toward it, and they shall come and join themselves to the Lord by an everlasting covenant that will never be forgotten (NRSV 50:2-5).
Declare ye among the nations, and publish, and set up a standard; publish, and conceal not: say, Babylon is taken, Bel is confounded, Merodach is broken in pieces; her idols are confounded, her images are broken in pieces. For out of the north there cometh up a nation against her, which shall make her land desolate, and none shall dwell therein: they shall remove, they shall depart, both man and beast. In those days, and in that time, saith the Lord, the children of Israel shall come, they and the children of Judah together, going and weeping: they shall go, and seek the Lord their God. They shall ask the way to Zion with their faces thitherward, saying, Come, and let us join ourselves to the Lord in a perpetual covenant that shall not be forgotten (KJV 50:2-5).
In the same way that the Babylonians inflicted God's justice on other people, they'll now have divine justice inflicted on them by another people. It's a restoration of how things used to be between God and Israel when the covenant was first made.