Introduction
We are in the final section of chapter 31 in Yirmiyahu - the great chapter of consolation. The prophet who was known as the prophet of wrath and calamity is privileged here to deliver a prophecy of redemption: the return of the children to their border, the rebuilding of the cities, a new covenant that will never be broken, and the rebuilding of Jerusalem, never to be destroyed again. We will proceed through the verses in order, primarily following the commentary of the Malbim, along with the insights of Rashi and the Radak.
Waymarks, Guideposts, and a Highway - The Road Back is Paved
הַצִּיבִי לָךְ צִיֻּנִים, שִׂמִי לָךְ תַּמְרוּרִים, שִׁתִי לִבֵּךְ לַמְסִלָּה דֶּרֶךְ הָלָכְתְּ, שׁוּבִי בְּתוּלַת יִשְׂרָאֵל שֻׁבִי אֶל עָרַיִךְ אֵלֶּה׃ - Set up waymarks for yourself, place guideposts for yourself, set your heart to the highway, the way you walked; return, O maiden of Israel, return to these cities of yours.
The Malbim explains: When preparing a road to be suitable for public travel, waymarks (tziyunim) are erected - what we would call signage today. They indicate that a right turn leads here, a left turn leads there, and the next fork takes you to a specific destination. When the road is upgraded further, guideposts (tamrurim) are planted along its sides. These were small palm trees (from the root tamar) planted on both sides of the road, serving as an unmistakable sign of a public thoroughfare; when travelers saw palm trees lining both sides, they knew it was a main highway. And when the road is improved even further, a paved highway (mesilah) is built - clearing away the stones and leveling the ground.
Therefore, the Holy One, blessed be He, says to the children of Israel seeking the way to the Land of Israel: You will surely find it through the waymarks, even more so through the palm guideposts, and even more so if you pay attention to the paved highway and see that a road has already been leveled here. All of these point you in the right direction. And if so - return, O maiden of Israel, from exile; return to these cities, which stand before you awaiting your return. The way is already paved to return to the Land of Israel.
There is an intriguing hint here in the wording of the Malbim, who writes: "And regarding this He said to the children of Israel who seek the way to the Land of Israel, will you not find it through the waymarks (tziyunim)?" Corresponding to this, it is written in Tehillim (69:36): "For God will save Zion (Tziyon) and build the cities of Judah, and they will settle there and inherit it" - first they settle in the land, and only afterward do they inherit it: settlement of the Land of Israel begins first, followed later by wars and inheritance. And through whom will the inheritance take place? The verse continues: "And the seed of His servants will inherit it" - servants, a lower spiritual level; and only afterward, "and those who love His name will dwell in it" - the God-fearing will dwell in it. Thus, at first the inheritance occurs on the level of servants rather than children, but those who settle in the land draw closer to Hashem, and ultimately "those who love His name will dwell in it."
A Female Encompasses a Male - The Land Courting Her Children
עַד מָתַי תִּתְחַמָּקִין הַבַּת הַשּׁוֹבֵבָה, כִּי בָרָא יְהֹוָה חֲדָשָׁה בָּאָרֶץ נְקֵבָה תְּסוֹבֵב גָּבֶר׃ - How long will you waver, O backsliding daughter? For Hashem has created a new thing in the land: a female shall encompass a male.
As it were, Hashem asks the Land of Israel: How long will you hide from the exiles? The Malbim explains that this metaphor depicts the land as female and the people who dwell within it as male. We have already found this expression: "For as a young man marries a maiden, so shall your children marry you" - the land is like a maiden, and those who come to settle in it are like a young man who marries her, denoting ownership. In the way of the world, where the man pursues and courts the woman, a nation typically strives to conquer a land through war if it wishes to dwell there - they court it, and they make the active effort.
In the Second Temple era, however, when they returned to their land, there was no conquest and no war: there was the royal decree of Cyrus and Darius, and as a result we took possession of the land. Thus, as it were, the land itself sought us out; it prepared itself for the male coming toward it. This is the "new thing" created: normally the female is pursued and courted by the male, but here the reality is reversed - "a female shall encompass a male," the female seeks out the male. The land seeks its children, without its children needing to march forth and wage war to conquer it. Regarding this, Hashem says: How long will you waver, O backsliding daughter, how long will you remain hidden without going out to seek your children?
Abode of Righteousness and Holy Mountain
כֹּה אָמַר יְהֹוָה צְבָאוֹת אֱלֹהֵי יִשְׂרָאֵל, עוֹד יֹאמְרוּ אֶת הַדָּבָר הַזֶּה בְּאֶרֶץ יְהוּדָה וּבְעָרָיו בְּשׁוּבִי אֶת שְׁבוּתָם, יְבָרֶכְךָ יְהֹוָה נְוֵה צֶדֶק הַר הַקֹּדֶשׁ׃ - Thus said the Lord of Hosts, the God of Israel: They shall yet say this word in the land of Judah and in its cities when I restore their captivity: May the Lord bless you, dwelling of righteousness, holy mountain.
Radak notes that this section, too, refers to the future, as do the sections following it until the passage of "The word that came to Jeremiah." The land of Judah is mentioned specifically because the Beit HaMikdash lies within its territory, and that is what the end of the verse references: "dwelling of righteousness, holy mountain." They will say: "May the Lord bless you" - the Beit HaMikdash will henceforth be blessed, and there will never again be destruction or a reality of exile.
Malbim explains: "When I restore their captivity" - when the cities return to their original stature. And why will the Lord bless it? "Dwelling of righteousness" - this is the reason: because righteousness, as it were, has planted its abode here; here righteousness has found its home. Mount Zion will be called "the holy mountain," for holiness has established its home here. And since these places will be sites of sanctity and righteousness, there will consequently be no further exile or destruction.
וְיָשְׁבוּ בָהּ יְהוּדָה וְכָל עָרָיו יַחְדָּו, אִכָּרִים וְנָסְעוּ בַּעֵדֶר׃ - And Judah and all its cities shall dwell in it together, farmers and those who travel with flocks.
"And they shall dwell in it" - in this righteousness and in this dwelling, Judah and all its cities shall dwell. The imagery portrays both the cities and the people as dwelling in the abode of righteousness, filled with justice and holiness. Even the farmers who till the soil, and even those who constantly travel far and wide - the shepherds with their flocks. Shepherds with flocks typically characterized thieves, while farmers characterized the unlearned, who were called *amei ha'aretz*, whose entire concern was mundane earthly labor. Says the prophet: both the farmers, deemed inferior in knowledge and spirituality, and the shepherds, deemed inferior due to dishonest conduct, will no longer wander from place to place. Instead, they will settle permanently in the dwelling of righteousness and conduct themselves with justice and integrity.
כִּי הִרְוֵיתִי נֶפֶשׁ עֲיֵפָה, וְכָל נֶפֶשׁ דָּאֲבָה מִלֵּאתִי׃ - For I have sated the weary soul, and every languishing soul I have replenished.
The soul of Israel, which was weary and thirsty in exile - Hashem says: I will now sate it from the springs of salvation, as Radak puts it. Malbim explains: whoever was weary from excessive labor, I will sate. "And every languishing soul" - a person lacking all their needs, whom I have replenished with everything required, so they will no longer need to rob or plunder. Radak explains that *da'avah* (languishing) is related to worry (*de'agah*): a soul anxious and aching from troubles, concerning which the Holy One, blessed be He, says: I have filled it with joy, and this will remove its anguish, suffering, and sorrow.
"Upon this I awoke" - Prophecy in Joy
עַל זֹאת הֱקִיצֹתִי וָאֶרְאֶה, וּשְׁנָתִי עָרְבָה לִּי׃ - Upon this I awoke and saw, and my sleep was sweet to me.
Rashi explains: Thus spoke Jeremiah - all the time I lay asleep and slumbering amidst prophecies of catastrophe (Jeremiah having been the prophet of wrath and calamity), here, when I finally receive a positive message describing the Redemption, "I awoke" from my slumber. These wondrous things are what awakened me.
Radak explains that prophecy generally comes to a prophet in a dream. He cites the Targum: "The prophet said: Concerning this good tidings of the days of consolation destined to come, I awakened and saw, and my sleep pleased me." Over this prophecy, where I suddenly see good tidings, I woke up and rejoiced, and then I went back to sleep and my sleep was sweet to me. For previously, his sleep had never been sweet: it had been a sleep of terrors, nightmare-ridden, filled with ominous prophecies. This time, however - "my sleep was sweet to me."
Malbim adds deeper insight: Jeremiah was unable to perceive his prophecy while awake because receiving prophecy in an awakened state requires being in a prophetic state of joy. When people sought to have the spirit rest upon a prophet, they would bring a musician: "as the musician played, the hand of the Lord came upon him." Jeremiah, who constantly envisioned only terrifying calamities, could not attain that joy, and therefore prophecy rested upon him only in dreams. But here, where the prophecy is one of joy and redemption, he says: "Upon this I awoke and saw" - this one I was able to see while awake, because I truly was in a state of joy. Afterwards I went back to sleep, "and my sleep was sweet to me," free from the night terrors that typically accompanied the grim prophecies.
Seed of Man and Seed of Beast - The Exile as Sowing
הִנֵּה יָמִים בָּאִים נְאֻם יְהֹוָה, וְזָרַעְתִּי אֶת בֵּית יִשְׂרָאֵל וְאֶת בֵּית יְהוּדָה זֶרַע אָדָם וְזֶרַע בְּהֵמָה׃ - Behold, days are coming, says Hashem, when I will sow the House of Israel and the House of Judah with the seed of man and the seed of beast.
Rashi explains: "The seed of man" refers to the good and intelligent; "and the seed of beast" refers to people whose actions resemble those of beasts. That is to say, I will sow them all, that they may all be Mine, both the upright and those who are not upright. And Yonatan translated: "I will establish them like human beings and grant them success like beasts." And what success does a beast have? Rashi explains: its sins are not held against it. In the same way, we will have the success that our sins will not be remembered or held against us.
Radak explains this in several ways: Just as from one coin come many coins, so too I will sow them - you plant one seed, and from it grows an orange tree full of oranges, all from a single seed. He will place His blessing upon them and multiply them, and there will be none among them who miscarries. He further explains that the vav of "and the seed of beast" is a vav of comparison, one corresponding to the other, as in, "Cold water to a faint soul, and good news from a far country" (Mishlei 25:25), meaning: the seed of man like the seed of beast, that mankind will multiply like beasts, and as it is written, "I will multiply them like a flock of men" (Yechezkel 36:37). Thus, this refers to their great increase.
The Malbim explains that the prophet is depicting their existence in exile as the state of a seed. When you plant a seed, at first it rots, decays, and decomposes, and only afterward does a great and magnificent tree grow from it. Thus, the exile corresponds to the rotting of the seed, for before rebirth there is always an aspect of absence and death. You, the House of Israel in exile, are like a seed, in a state of absence. And even though I have sown you and dispersed you throughout all the lands until you have ceased to function as a nation - know that this was not for the sake of scattering, but for the sake of gathering, for the sake of growth. Just as a person takes a seed and places it in the ground, seemingly ruining it, yet it is all to sprout a great and magnificent tree. "The seed of man and the seed of beast" - from both the prominent among them and the lowly among them, from all of Israel, the redemption will sprout.
וְהָיָה כַּאֲשֶׁר שָׁקַדְתִּי עֲלֵיהֶם לִנְתוֹשׁ וְלִנְתוֹץ וְלַהֲרֹס וּלְהַאֲבִיד וּלְהָרֵעַ, כֵּן אֶשְׁקֹד עֲלֵיהֶם לִבְנוֹת וְלִנְטֹעַ נְאֻם יְהֹוָה׃ - And it shall come to pass that just as I watched over them to uproot, to pull down, to overthrow, to destroy, and to bring evil, so will I watch over them to build and to plant, says Hashem.
"Just as I watched over them" - just as I was diligent to uproot and pull down, so will I be diligent to build and to plant. The Malbim explains: Uprooting (netishah) is pulling saplings from their place, and it is for the sake of planting; tearing down (netitzah) is for the sake of building. That is, even what occurred until now - "to uproot and pull down" - was for the sake of building: when you want to build a house where a ruin stands, you must first tear it down and only then build. And when you want to create a beautiful orchard where damaged trees stand, you must first pull them up and uproot them, and only then plant a beautiful, proper plantation. This is the very same concept as the seed that lies in the ground and decomposes, and afterward sprouts a magnificent tree.
"Fathers Have Eaten Sour Grapes" - When Is the Iniquity of the Fathers Visited?
בַּיָּמִים הָהֵם לֹא יֹאמְרוּ עוֹד אָבוֹת אָכְלוּ בֹסֶר וְשִׁנֵּי בָנִים תִּקְהֶינָה׃ כִּי אִם אִישׁ בַּעֲוֺנוֹ יָמוּת, כָּל הָאָדָם הָאֹכֵל הַבֹּסֶר תִּקְהֶינָה שִׁנָּיו׃ - In those days they shall no longer say, "Fathers have eaten sour grapes, and the children's teeth are set on edge." But every man shall die for his own iniquity; every person who eats sour grapes, his teeth shall be set on edge.
Radak explains: "Fathers have eaten sour grapes, and the children's teeth are set on edge" is a parable for the sinner. In earlier generations people would say: Our fathers sinned and are no more, and we have borne their iniquities. After all, Menasheh was already gone, and yet the exile came about because of the sins of Menasheh, as the prophet mentions several times. The fathers ruined and sinned, and the children suffer.
Radak raises a difficulty: It is true that one of the attributes of the blessed Creator is that He "visits the iniquity of fathers upon children, to the third and fourth generation" - how, then, can it be that in those days they will no longer say this proverb? He answers: Indeed, that is so, but for that to occur two conditions must be met. The first condition: that the children cling to the deeds of their fathers. The second condition, and this is a condition not many know: that it must concern the grave sin of idolatry (avodah zarah). And how do we know this? The Rambam in Moreh Nevuchim deduces this from the verse there, "For Hashem your God is a jealous God," and "a jealous God" is stated only regarding idolatry, where the Holy One, blessed be He, is, so to speak, zealous when people worship idols. Thus, for "the fathers have eaten sour grapes and the children's teeth are set on edge" to apply, the children must cling to the deeds of their fathers, and it must be a grave sin such as idolatry.
Radak continues: Here the Holy One, blessed be He, promises that in the future our hearts will be whole with Hashem, and the earth will be filled with the knowledge of Hashem, and through this sinners will become few. Not only will they become few, but grave sins like idolatry will no longer exist at all. And even for ordinary sinners, the Holy One, blessed be He, will delay punishment - "and the sinner who is a hundred years old shall be accursed" (Yeshayahu 65:20), meaning that even a hundred years will be considered young, and only at such an age will he be cursed. If so, all the more so will a son not be punished for his father's sins: even if his father sinned, the son's teeth will not be set on edge by the sour grapes his father ate.
The Malbim explains this wonderfully and refers us to Yechezkel 18:2. Our Sages state: Four things did Moshe say, and four prophets came and abolished them. One of them is this: Moshe said, "He visits the iniquity of the fathers upon the children," and Yechezkel came and abolished it - "The soul that sins, it shall die." And what is the simple meaning of this? Since that verse was spoken regarding idolatry, as the Radak noted and as explained by the Rambam, and Yechezkel lived during the era of the Men of the Great Assembly, and in the time of the Great Assembly they had already abolished the yetzer hara for idolatry - Yechezkel consequently came and abolished "The fathers have eaten sour grapes," for this principle applied only to idolatry. Once the inclination for idolatry was nullified, this rule was nullified, and each person dies for his own sin alone.
And this is what is stated in our passage: "In those days they shall say no more: 'The fathers have eaten sour grapes, and the children's teeth are set on edge'" - this expression will no longer have any relevance, because it applied only to idolatry, and in those days the evil inclination for idolatry was eliminated, just as occurred during the Second Temple era. Therefore, it will no longer be possible for fathers to eat sour grapes and children's teeth to be blunted; rather, each person shall die for his own iniquity, and children will not be punished for the sins of their fathers.
A New Covenant - Not a New Torah
הִנֵּה יָמִים בָּאִים נְאֻם יְהֹוָה, וְכָרַתִּי אֶת בֵּית יִשְׂרָאֵל וְאֶת בֵּית יְהוּדָה בְּרִית חֲדָשָׁה׃ - "Behold, days are coming," declares the Lord, "when I will make a new covenant with the house of Israel and with the house of Judah."
What is a "new covenant"? The Radak explains: A covenant that will be renewed by Hashem. The covenant He made with us at Mount Sinai was broken, and now it is being renewed. And anyone who claims that the prophet was prophesying about a future new Torah, unlike the Torah given at Sinai, is mistaken. For our Sages say: What was the covenant I made with their fathers? "They broke My covenant" - whereas this covenant, they will not break. Look at what follows: "I will place My Torah within them, and upon their heart I will write it" - so that it will never be forgotten by them. Thus, this does not refer to a new Torah, but rather to something that until now we did not properly observe, but from now on we will observe.
The Radak notes further: What does Malachi, the seal of the prophets, write at the very conclusion of his prophecy? "Remember the Torah of Moshe My servant, which I commanded him at Chorev for all Israel, statutes and ordinances" - and all this is a prophecy for the future. If there were to be a new Torah, why mention "the Torah of Moshe My servant"? Clearly, that is not the intention; the Torah will never be replaced, nor will there ever be another Torah. He likewise concludes: "Behold, I send you Eliyahu the prophet" - showing that there will never be a new Torah, but rather the very one given at Mount Sinai, "which I commanded him at Chorev," will endure forever.
What, then, is being renewed? The covenant. A covenant is an agreement, a treaty, a bond and connection between us and Hashem, and this bond had weakened. The Holy One, blessed be He, says: In this sense it will be a new covenant - this covenant will never be broken; the agreement between us will no longer be violated as it was until now. And how will this be expressed? The Malbim explains: In the past there was the possibility to sin, but in the future there will be no possibility to sin at all. Thus, this refers to a new bond between us and Hashem, an unbreakable connection. For if there is a possibility of sinning, there is a possibility of disconnection; but if there is no possibility of sinning, it is an eternal bond.
לֹא כַבְּרִית אֲשֶׁר כָּרַתִּי אֶת אֲבוֹתָם בְּיוֹם הֶחֱזִיקִי בְיָדָם לְהוֹצִיאָם מֵאֶרֶץ מִצְרָיִם, אֲשֶׁר הֵמָּה הֵפֵרוּ אֶת בְּרִיתִי וְאָנֹכִי בָּעַלְתִּי בָם נְאֻם יְהֹוָה׃ - "Not like the covenant that I made with their fathers on the day I took them by the hand to lead them out of the land of Egypt, which covenant of Mine they broke, though I was a lord to them," declares the Lord.
The Malbim explains: This covenant will not be like the covenant I made with their fathers, because they broke that covenant. And why did they break it? Because back then, they were not yet ready and fit for perfection and rectification. Pay close attention to the wording of the verse: "On the day I took them by the hand to lead them out of the land of Egypt." Whom do you hold by the hand to lead out? Only a disabled person or a child. A healthy, capable person does not need someone to hold his hand. In other words, in their state at that time they were not worthy, and I took them out in haste before they would deteriorate completely; for had they lingered any longer, they would have sunk into the fiftieth gate of impurity, and it would have been impossible to redeem them.
"Which covenant of Mine they broke" - since the nature of the nation redeemed from Egypt was still attached to evil, as in "the Egyptians dealt ill with us," and they had learned idolatry from them, they broke the covenant. Consider: forty days after the Exodus, they made a molten calf and violated the condition. "Though I was a lord to them" - I acted toward them as a master over them against their will, not through willing acceptance. And the Radak cites in the name of his father that whenever the root b-'-l is paired with the preposition bet, as in "ba'alti vam," it carries a derogatory connotation, where ba'alti is like bachalti (I loathed), meaning: "And I grew disgusted with them, declares the Lord" - an expression of revulsion, like something a person finds abhorrent.
Four Innovations in the New Covenant
כִּי זֹאת הַבְּרִית אֲשֶׁר אֶכְרֹת אֶת בֵּית יִשְׂרָאֵל אַחֲרֵי הַיָּמִים הָהֵם נְאֻם יְהֹוָה, נָתַתִּי אֶת תּוֹרָתִי בְּקִרְבָּם וְעַל לִבָּם אֶכְתְּבֶנָּה, וְהָיִיתִי לָהֶם לֵאלֹהִים וְהֵמָּה יִהְיוּ לִי לְעָם׃ - "For this is the covenant that I will make with the house of Israel after those days," declares the Lord: "I will place My Torah within them, and upon their heart I will write it; and I will be their God, and they shall be My people."
The first innovation: "I will put My Torah within them" - they will observe the Torah out of intellectual awakening, until it becomes second nature to them, residing within them. For today, when a person observes the Torah, he experiences internal resistance, yet he does it nonetheless because it is the will of Hashem. We have already mentioned the teaching of the Vilna Gaon, that a person facing a dilemma who does not know which of two options to choose should look at which side he leans toward and desires, and choose the opposite side. For our reality today is one of total identification with evil. And as in the wording of Rav Nissim Gaon's vidui: "And just as it is Your nature to forgive" - so it is man's nature to sin. Man's nature is drawn toward evil; within him good and evil are intertwined. Here, however, the prophet says that the Torah will be observed out of intellect and will be like something natural residing within them, infused in them and part of who they are.
And to such an extent - "and upon their hearts I will write it": there will be no need to write the Torah in a book with ink; rather, it will be inscribed upon their hearts. The heart represents free will and the sovereign power within the soul, and it is considered the ruler over all the limbs. When the Torah is inscribed upon the heart, it turns out that upon the ruler of the entire body the Torah is written, as though there were no other side and no other choice: the laws of the Torah will be engraved within them and become their very nature.
Incidentally, this corresponds beautifully to what is said regarding Avraham Avinu. We discussed in the past that welcoming guests is greater than receiving the Shechinah, and from where do we derive this? From Avraham saying to Hashem, "Please do not pass on from Your servant," for I have guests to welcome - we see that Avraham leaves Hashem to go welcome guests. And we asked: we learn this from Avraham, but how did Avraham know? From where did he have the audacity to leave the Holy One, blessed be He, and go attend to guests? And we explained that this is no difficulty at all, because for Avraham the reality was the exact opposite of what the Vilna Gaon described regarding us: when Avraham felt his limbs drawn toward a certain action, he knew that this was Hashem's will. Therefore, when he saw that he was drawn to welcome guests, he knew that Hashem's will was welcoming guests, so he said, "Please do not pass on from Your servant," and ran to welcome them. And how did he know? For it is written of Avraham that his two kidneys were like two wellsprings pouring forth Torah. Look how marvelous this is, and how well it aligns with "I will put My Torah within them and upon their hearts I will write it": as the Malbim phrases it, they will not need a book written with ink; everything will be engraved upon their hearts. This was Avraham's reality, that everything was engraved upon his heart and his kidneys, and so whenever his body was drawn to something, he knew that this was the will of Hashem.
The second innovation: "And I will be their God, and they will be My people." The Malbim explains: in our current order of divine providence, everything begins with an awakening from below, followed by an awakening from Above - first you must take the initiative, and only then will you see divine assistance. Here, however, the order is reversed: first "and I will be their God," and only then "and they will be My people." Out of Hashem's lovingkindness, the awakening toward us will come first. The reason is simple: since there will no longer be any possibility of choosing evil, there is no impediment to Hashem being our God first, and only then our becoming His people.
וְלֹא יְלַמְּדוּ עוֹד אִישׁ אֶת רֵעֵהוּ וְאִישׁ אֶת אָחִיו לֵאמֹר דְּעוּ אֶת יְהֹוָה, כִּי כוּלָּם יֵדְעוּ אוֹתִי לְמִקְּטַנָּם וְעַד גְּדוֹלָם נְאֻם יְהֹוָה, כִּי אֶסְלַח לַעֲוֺנָם וּלְחַטָּאתָם לֹא אֶזְכָּר עוֹד׃ - And no longer will each man teach his fellow and each man his brother, saying, 'Know Hashem,' for they all will know Me, from the least of them to the greatest of them, says Hashem; for I will forgive their iniquity, and their sin I will remember no more.
The third innovation: no error in the ways of Hashem will be possible due to a lack of teachers to instruct us and guide us on the proper path. "And no longer will each man teach his fellow, saying, 'Know Hashem'" - they will have no need for anyone to teach them knowledge, for "they all will know Me, from the least of them to the greatest of them."
And the fourth innovation: they will also have no fear that I might remember their iniquities. For we have committed sins, and perhaps the Holy One, blessed be He, will not forget how we provoked Him? Regarding this it is said, "for I will forgive their iniquity." According to the approach of the Malbim, this cannot refer to iniquities committed in the future, for we have already established that there will be no free choice toward evil and no yetzer hara; rather, it refers to iniquities committed in the past. "I will forgive their iniquity" - referring to intentional sins; "and their sin," as chatat denotes unintentional sin, "I will remember no more" - for an unintentional sin they will not even need forgiveness, as I will not remember it at all; whereas an iniquity, being intentional, requires forgiveness, and regarding this Hashem says that He will forgive them.
The Radak notes: it does not say here that everyone will be equal in wisdom, for that is impossible, and certainly the small will not be as wise as the great. If so, what is meant by "they all will know Me, from the least of them to the greatest of them"? It means knowing Hashem - fearing Him and walking in His ways. Do not think that after the arrival of the Redeemer, wisdom will be equal among all people; rather, in knowing Hashem and walking in His ways all will be equal, from the greatest sage to the simple person - all will walk in the way of Hashem.
Like the Laws of Heaven and Earth - The Eternity of Israel
כֹּה אָמַר יְהֹוָה נֹתֵן שֶׁמֶשׁ לְאוֹר יוֹמָם, חֻקֹּת יָרֵחַ וְכוֹכָבִים לְאוֹר לָיְלָה, רֹגַע הַיָּם וַיֶּהֱמוּ גַלָּיו, יְהֹוָה צְבָאוֹת שְׁמוֹ׃ - Thus said Hashem, Who gives the sun for light by day, and the fixed laws of the moon and stars for light by night, Who calms the sea when its waves roar, Hashem of Hosts is His Name.
The phenomena mentioned here are enduring and eternal, existing from of old and unchanging. The sun shines constantly for light by day. "The fixed laws of the moon and stars for light by night" - the Radak explains that they are called chukot because the laws governing their movements reflect a wondrous wisdom that man cannot fully fathom. "Who calms the sea when its waves roar" - the Holy One, blessed be He, calms the waters of the sea or brings about the roaring of the waves; and some explain that this refers to Hashem splitting the sea for Israel, calming the waves even as they roared.
אִם יָמֻשׁוּ הַחֻקִּים הָאֵלֶּה מִלְּפָנַי נְאֻם יְהֹוָה, גַּם זֶרַע יִשְׂרָאֵל יִשְׁבְּתוּ מִהְיוֹת גּוֹי לְפָנַי כָּל הַיָּמִים׃ - If these laws depart from before Me, says Hashem, then the offspring of Israel also shall cease from being a nation before Me for all time.
Just as these fixed laws - the sun to illuminate the day, the moon and stars to illuminate the night, the sea and its waves - are perpetual, engraved into nature, and will never cease, so too Israel shall never cease from being a nation before Me, from being My people, forever.
The Malbim explains two specific points here. First, there will be no possibility whatsoever of doing evil. Just as the laws of nature do not change, so too their deeds will not change; rather, doing good will become second nature to them, and they will be incapable of doing evil. There will be no reality of evil and no free choice to do evil. Second, their choice will never waver; their choice will forever be for the good. He is speaking of the future, when there will no longer be an option of choosing evil, but they will always choose to be "a nation before Me all the days" - a nation serving Hashem, standing before Him to minister to Him all the days.
Love Without Limit and Beyond Comprehension
כֹּה אָמַר יְהֹוָה אִם יִמַּדּוּ שָׁמַיִם מִלְמַעְלָה וְיֵחָקְרוּ מוֹסְדֵי אֶרֶץ לְמָטָּה, גַּם אֲנִי אֶמְאַס בְּכָל זֶרַע יִשְׂרָאֵל עַל כָּל אֲשֶׁר עָשׂוּ נְאֻם יְהֹוָה׃ - So said Hashem: If the heavens above can be measured, and the foundations of the earth below can be searched out, then I too will reject all the seed of Israel for all that they have done, says Hashem.
The Radak notes: regarding the heavens, the term "measuring" applies, because the heavens are stretched out above us, as in the phrase "the heavens are spread above us," so in theory one could attempt to measure them. And Hashem says: try to measure the heavens! And indeed, to this day, with all of modern science's most advanced tools, no one has succeeded in measuring the heavens. Whereas regarding the foundations of the earth - the Malbim explains that measuring applies to them, for scientists discuss the size of the Earth and the Earth's core, but searching them out? All our knowledge about the Earth's core and what lies deep within consists of estimates and hypotheses. Scientists recently discovered that there is water deep down, and they do not know where it came from, which is one of the findings that leads - as Rabbi Zamir Cohen discusses - to the conclusion that the entire earth was flooded with water at some point in time, essentially confirming the account of the Deluge. One may know the external dimensions, but to search inside - who has truly investigated it? One would have to descend deep into the interior to really explore what is happening there. Thus: no one has succeeded in measuring the heavens, and while people have managed to measure the earth, they have not succeeded in searching out its foundations. And Hashem says: only when these things are achieved will I reject all the seed of Israel. In other words, how complete will this forgiveness and pardon be? Just as it is impossible ever to measure the heavens or search out the depths of the earth, so too do not imagine that there is any possibility that I will not forgive them. Rather, this is an eternal promise that I will never reject them, and I will forgive them for all they have done.
The Malbim illuminates the profound depth here wonderfully: this phrasing expresses the Holy One, Blessed be He's infinite love for us. The Holy One, Blessed be He, says: the love that I have for the Jewish people has no limit in terms of quantity. Just as measuring the heavens yields no finite end, since you never reach a final measurement, so My love for you is boundless, beyond measure. And if you attempt to comprehend what this love stems from - which would require investigation - about this He says: it is also beyond searching out. "And the foundations of the earth below can be searched out" - if you try to investigate why the Holy One, Blessed be He, loves us, you will never be able to reach any rational explanation.
From here arise two fundamental principles. First, something that has no limit in quantity cannot be negated by sins, because sins have a limit and a finite quantity, whereas My love for you is unlimited, and a limited thing can never nullify an unlimited thing. The infinite love will always surpass the sins, for no matter how grave they are, they are always finite, while the love is forever boundless. Second, something that is beyond searching out and rational cause, the Malbim explains, is an intrinsic, essential quality (a segulah), and can never be undone. For when something is dependent upon a specific reason or cause, once the reason disappears, the thing ceases to exist; when its cause is removed, it is canceled along with it. But when something transcends rational cause, there is no cause that could ever undo it.
The Rebuilding of Jerusalem, Never to Be Destroyed Again
הִנֵּה יָמִים בָּאִים נְאֻם יְהֹוָה, וְנִבְנְתָה הָעִיר לַיהֹוָה מִמִּגְדַּל חֲנַנְאֵל שַׁעַר הַפִּנָּה׃ - Behold, days are coming, says Hashem, when the city shall be built for Hashem, from the Tower of Chananel to the Corner Gate.
"And the city shall be built for Hashem" - this part of Jerusalem will not belong solely to the territory of Binyamin, but will be "for Hashem," entirely dedicated to the entire Jewish people, holy to Hashem.
וְיָצָא עוֹד קָו הַמִּדָּה נֶגְדּוֹ עַל גִּבְעַת גָּרֵב, וְנָסַב גֹּעָתָה׃ - And the measuring line shall go out further straight ahead over the hill of Gareiv, and turn toward Goah.
"The measuring line" is the rope used for measuring, and it will extend to the place called the hill of Gareiv, "and turn" - it will encircle around. In simple terms: the area will expand, and the city will grow.
וְכָל הָעֵמֶק הַפְּגָרִים וְהַדֶּשֶׁן וְכָל הַשְּׁדֵמוֹת עַד נַחַל קִדְרוֹן עַד פִּנַּת שַׁעַר הַסּוּסִים מִזְרָחָה, קֹדֶשׁ לַיהֹוָה, לֹא יִנָּתֵשׁ וְלֹא יֵהָרֵס עוֹד לְעוֹלָם׃ - And the whole valley of the corpses and the ashes, and all the fields as far as the brook of Kidron, as far as the corner of the Horse Gate eastward, shall be holy to Hashem; it shall not be uprooted nor overturned any more forever.
What is "the valley of the corpses"? Rashi explains: the valley where the corpses of Sancheriv's army fell. And "the ashes" refers to the place outside Jerusalem where the ashes from the altar were deposited (shefech hadeshen); all of this will now be incorporated inside the walls - Jerusalem will expand, and everything will be enclosed within the walls. The Radak brings another explanation, that "the ashes" (hadeshen) refers back to the corpses: the Assyrian army who had been robust and thriving (medushanim), and the place where they died is destined to become part of Jerusalem.
And what are "the fields" (hashedemot)? According to the plain meaning - the fields adjacent to the city, all of which will now be inside the city and inside the wall. Another explanation is given by Targum Yonatan: "arita", as in "arita dedelaye" (an irrigation channel), referring to the aqueduct used to water the fields, which will also be included within the wall.
"As far as the corner of the Horse Gate eastward" - Radak cites Targum Yonatan, who translates this as "the gate of the king's racetrack" (tar'a beit reisa demalka). A beit ris is a measure of seventy reeds, each reed being six amot and a zeret, which is roughly two hundred meters. This was the place where horses ran: the king would go out there with his horsemen, and it was a level stretch where the horses would gallop. All these places will be "holy to Hashem; it shall not be uprooted nor overturned any more forever" - they will endure eternally. It will not be like the First Temple and the Second Temple, which were destroyed; rather, the rebuilding of the city and the rebuilding of the Temple will never be overturned or uprooted ever again.
In summary:
In this part of the chapter, the prophecy portrays a paved highway marked with waymarks, guideposts, and a thoroughfare for the return of the children, and a land that itself pursues its children - "a female shall court a male." The cities will return to their former stature and become a habitation of righteousness and a holy mountain; the farmers and shepherds will conduct themselves with justice and integrity, and the weary soul will be sated. Yirmiyahu, who had always experienced his prophecies in dreams accompanied by grief, is privileged here to see them in an awake state, out of joy. The exile is revealed to be a sowing whose decomposition gives rise to a tree, and the uprooting and breaking down are revealed as preparation for building and planting. No longer will they say, "The fathers have eaten sour grapes," for the inclination toward idol worship will be abolished; and a new covenant will be forged - not a new Torah, Heaven forbid, but an unbreakable bond: Torah within their inward parts and inscribed naturally upon their hearts, a redemption initiated from Above, knowledge of Hashem for all, from their smallest to their greatest, and complete forgiveness. And just as the fixed laws of the sun and moon will never depart, so too the seed of Israel will never cease; and just as the heavens cannot be measured nor the foundations of the earth searched out, so too Hashem's love for us is beyond limit and beyond rationale - and therefore can never be annulled. And ultimately: the city will be built for Hashem and expand, and everything will be holy to Hashem, never to be uprooted or destroyed ever again.