Chapter 58 of Yeshayahu is one of the most piercing chapters of prophetic rebuke. The Holy One, blessed be He, commands the prophet to call out in a loud voice and admonish the people, and the core problem becomes immediately clear: it is neither outright heresy nor an open abandonment of the Torah, but rather a service of Hashem that is entirely lip service. The people seek Hashem day after day, ask questions, fast and afflict themselves, and even complain about why their prayers go unanswered. To this the prophet responds: all of this is mere externality. Let us proceed through the verses in order.
קְרָא בְגָרוֹן אַל־תַּחְשֹׂךְ כַּשּׁוֹפָר הָרֵם קוֹלֶךָ וְהַגֵּד לְעַמִּי פִּשְׁעָם וּלְבֵית יַעֲקֹב חַטֹּאתָם׃ - Cry aloud with a full throat, hold not back; raise your voice like a shofar, and declare to My people their rebellion, and to the house of Yaakov their sins.
The Holy One, blessed be He, tells the prophet: Rebuke the people, raise your voice over them like a shofar, whose sound is heard from afar. Seemingly, it should have said "cry with your mouth"; Radak explains that since the source of speech is in the throat, Scripture attributes the expression to the throat, as in "the high praises of God in their throat" and "I am weary with my crying, my throat is parched." "Hold not back" means that the calling must be continual.
"And declare to My people their rebellion" - Rashi explains that these are the Torah scholars, whose unintentional errors are considered rebellions, for an error in Torah study is deemed willful. "My people" are those who serve Me, and to them you must declare their rebellion, for even their unintentional errors are accounted as willful sins. "And to the house of Yaakov their sins" - "the house of Yaakov" always denotes the lower tier of the Jewish people, for "Yisrael" connotes nobility and dominion, whereas "Yaakov" connotes the heel (ekev), the lower level. When referring to women, "the house of Yaakov" refers to the women; when referring to the nation as a whole, "the house of Yaakov" refers to the unlearned (amei ha'aretz), those who do not engage in Torah study. For them, even an intentional transgression is considered an unintentional error; thus it says "their sins" (chatotam), a term denoting unintentional sin. Do they not commit willful transgressions? Of course they do, but because such a person is unlearned and entirely unaware of the halachah, even his willful deed is not done out of malice to rebel against the halachah, and therefore it is accounted as an error.
The Malbim examines the precision of these expressions: "Cry with a full throat" - in a powerful voice. "Hold not back" - let the calling be constant. "Raise your voice like a shofar" - let the voice grow progressively stronger, like the sound of the shofar at Mount Sinai, which grew exceedingly loud. Typically, when a person proclaims something, he shouts loudly the first time, and on subsequent occasions he lowers his volume, since many have already heard. The Holy One, blessed be He, says to him: with you it shall be the reverse. Start with a powerful voice, and increase it more and more from there. Do not relent and do not say, "they have surely heard by now"; rather, let the cry become ever louder.
The Malbim further explains: what is the meaning of "raise your voice like a shofar"? A shofar has no sound of its own. If you set a shofar down in place, does it produce a sound? Its sound is nothing other than the breath of the one who blows it. In the same way, the prophet is like a shofar: Who speaks from his throat? The Shechinah speaks from within his throat. "Raise your voice like a shofar" - be like a shofar, through which the Holy Shechinah sounds Her voice, and the voice of Hashem speaks through him. Furthermore, the shofar produces a fractured, wailing, trembling blast, and this sound is meant to awaken repentance, as it is written: "Can a shofar be blown in a city and the people not tremble?" "Cry like a shofar" means: cause the people to tremble, awaken them to repentance.
And how are you to do this? "And declare to My people their rebellion." The word "pesha" (rebellion) denotes intentional defiance, and here it refers to sins between man and God; therefore it says "My people" - in that they are My nation, and the offenses are directed against Me. "And to the house of Yaakov their sins" - here He addresses them as a collective, as the house of Yaakov, and the sin is against the house of Yaakov itself, meaning interpersonal transgressions between man and his fellow.
וְאוֹתִי יוֹם יוֹם יִדְרֹשׁוּן וְדַעַת דְּרָכַי יֶחְפָּצוּן כְּגוֹי אֲשֶׁר־צְדָקָה עָשָׂה וּמִשְׁפַּט אֱלֹהָיו לֹא עָזָב יִשְׁאָלוּנִי מִשְׁפְּטֵי־צֶדֶק קִרְבַת אֱלֹהִים יֶחְפָּצוּן׃ - Yet Me they seek day after day, and desire knowledge of My ways; like a nation that performed righteousness and did not forsake the justice of its God, they ask Me for righteous judgments, desiring the nearness of God.
Seemingly, it might sound as if this is already describing the situation after they repented: they seek Hashem day after day, desire knowledge of His ways, ask for righteous laws, and desire closeness to God. But this is not so. All of this is a lament of the Holy One, blessed be He, over the deteriorating state of the people. "Yet Me they seek day after day" - as it is written: "They flattered Him with their mouth, and lied to Him with their tongue." Ostensibly, the praises of God are in their throat, as though they seek and wish to draw close to Him, blessed be He, but in truth this is nothing more than an external facade. "Desire knowledge of My ways" - as though they go to consult the sages for directives, like someone who genuinely intends to observe them. They constantly inquire about righteous laws: how to do this, how to tithe straw and salt. And then, when they fast and receive no answer, they raise objections: "Why have we fasted and You have not seen?" To this the Holy One, blessed be He, answers that even their fasting finds no favor before Him; and this is the underlying theme of the entire remainder of the chapter, a single continuous argument.
Radak explains: they seek Me day by day and desire knowledge of My ways, but it is all lip service and not from the heart, in speech and not in deed. For a person who practices righteousness and justice, it is fitting to inquire and know precisely the parameters of the obligation, in order to know how to act and how to conduct oneself. But one who has no intention of fulfilling it - why does he ask? On the contrary, Radak says: by inquiring, he doubled his iniquity. Had you not asked at all, it would still be somewhat understandable; but if you ask with no intention whatsoever of fulfilling it, it is far more infuriating, for you created the illusion that you were about to act.
A parable illustrates this: A man went to buy a refrigerator. He asked the price, and they told him 3,500. He began to haggle, pressing and pressing until he got the price down to 2,800. He wrote checks and took the refrigerator. The first check bounced. The seller thought it might be a misunderstanding. The second check bounced as well. He called the buyer and said: "What is this? You spent a full hour pressuring me to lower the price, and now the checks are bouncing?" He replied: "I am sorry, I am not trying to cheat you; I simply have no money to pay." The seller said: "You have no money to pay? Then why did you waste my time for an entire hour?" He replied: "I wanted to minimize your loss! It pained me that you should lose 3,500; this way you only lost 2,800." Exactly so: someone who inquires and shows interest like one who wants to fulfill, and then does nothing, is far more aggravating. "Behold, in his inquiring he doubled his iniquity."
Malbim explains that this verse explains the reason for the previous one: Why "Cry aloud, spare not, lift up your voice like a shofar"? Because the people's problem is that they do not recognize their sin at all; they are unaware that what they are doing is a transgression. Regarding the mitzvot between man and God, the Holy One, blessed be He, says, "Yet they seek Me daily" - they believe they fulfill their obligation through the mere act of seeking and investigating the commandments of Hashem. A person may produce very impressive pilpulim on all kinds of commandments I have commanded, but in practice? In practice, that is another story: he has no time, he is busy, he has no desire. If so, why all the study? For the sake of the intellectual exercise alone. There are sefarim where it is written, "for intellectual exercise only, and no halachic conclusions should be drawn from this," where the intention is to prevent people from reaching an erroneous halachic conclusion. But there are those whose entire study is like this: merely for intellectual sparring, with no intention of implementing even a fraction of it.
And corresponding to "and the house of Jacob their sins," which according to Malbim refers to sins between man and his fellow, it says, "and they desire to know My ways." For the mitzvah regarding interpersonal relationships is "and you shall walk in His ways" - just as He is merciful, so shall you be merciful; just as He is gracious, so shall you be gracious. It suffices for them that they desire to know what the Holy One, blessed be He, wants and what the proper path is between man and his fellow. One may have elaborate analyses in the laws of guarding one's tongue, the laws of lashon hara, and all kinds of strictures, yet in actual practice he does nothing at all. Only "they desire to know My ways" - theoretical knowledge alone, but to act and implement, not in the least.
"Like a nation that did righteousness" - corresponding to commandments between man and God; "and did not forsake the ordinance of their God" - corresponding to commandments between man and his fellow. He acts as if he has already fulfilled His commandments, but it is all merely outward lip service. Therefore, "they ask of Me righteous ordinances" - in interpersonal matters, what the law is and how one ought to act with justice; "and they desire the closeness of God" - as if seeking how to cleave to the Master of the World, in matters between man and God, as though they had practiced righteousness and justice and had not violated a single prohibition.
Malbim explains the progression: mishpat (justice) is what a person does according to the baseline law, while tzedek (righteousness) is going beyond the letter of the law. There is what you are entitled to by strict law, and there is what is granted to you out of benevolence. One who performs justice appropriately investigates and seeks righteousness - that is, going beyond the letter of the law. But one who does not even fulfill basic justice, how can he seek to go beyond the letter of the law? First fulfill the strict law, and only then seek pious stringency; first fulfill the halachah, and only then seek chumrot. Yet they come seeking righteousness while they have not even performed basic justice. How can one who abandons justice, who robs and steals, begin to seek righteousness and act beyond the letter of the law?
So too with the next level: tzedakah also alludes to the fulfillment of mitzvot between man and God, such as tzitzit and tefillin, which one is duty-bound to perform out of basic righteousness. By contrast, "closeness of God" is the exalted level - "And as for me, God's closeness is my good" - the level of the tzaddikim and the ascetic pietists who are truly close to Him, blessed be He. One who has performed righteousness can aspire to closeness to God, but one who has not fulfilled even the commandments he is obligated to perform, how can he seek closeness to God? Thus, there are three levels here: justice, righteousness, and closeness to God. You have not yet observed basic justice, and you seek righteousness? You have not yet done righteousness, and you are already seeking closeness to God? The foundation has not been laid, and yet they already seek high and sublime levels.
In truth, this can also be said of our own generation, which is a generation of superficiality. Rav Pincus, of blessed memory, defined our generation as an "instant" generation. In the past, one had to work and invest effort into everything; today, a person wants all of Shas downloaded onto his hard drive so that he already knows it; he wants to become a tzaddik in a single moment. Everything must be short, everything immediate. And because of this, we have also become a generation of superficiality. Notice this even in the material realm: speak to any technician today and he will tell you that they no longer make things like they used to. They produce a beautiful, glossy exterior, but inside it is all junk that lasts two or three years before being thrown out. This is true of washing machines, air conditioners, and everything else. In the past they built durable things; today everything is on the surface. And unfortunately, the same applies to the service of Hashem: a person serves his Creator only on the outside, seeking lofty levels, attainments, and spiritual heights, while he lacks the very foundation.
This is also evident in the approach to learning. In the past, people at least knew the basics; they knew how to learn a Gemara. A boy entering yeshivah ketanah knew the shakla v'tarya - what the Gemara asked, how it answered, what it asked next, and how it resolved it. Today? He immediately consults Rav Shimon on the sugya, or the Ketzot. Wait, pause before Rav Shimon: Can you explain what the Gemara asked and what the answer was? How did you jump ahead to that? This is how Rav Michel Yehuda Lefkowitz used to teach, and the Chazon Ish held his method of learning in high regard, sending students to learn from him in Ponevezh. That was the path: first and foremost, learn the Gemara. But flashiness and superficiality are more alluring: some clever pilpul, a sharp question.
The same applies to the performance of mitzvot. We seek stringencies and beautifications more than in the past: looking for an etrog without the slightest spot, searching for an extraordinary lulav. But how much heart is invested in the fulfillment of the mitzvah? Is this how mitzvot were performed in the past? Read in the Mishnah in Tractate Sukkah how the synagogue attendant would distribute the lulav to them: tossing it before them. Imagine if someone were to toss a lulav today; they would throw him out the door: "Am I supposed to shake this?" But their service of Hashem was internal; they did not need the outer packaging; everything was genuine. Similarly, the author of Even Sapir describes his visit to Yemen some one hundred and fifty or two hundred years ago, standing stunned: the gabbai arrived at the synagogue on Sukkot with a sack, emptied it onto the floor, and fifty or sixty etrogim tumbled out, and each person simply took an etrog. In our world, where is the cotton wool, where is the protective box, where is the meticulous care? This is not to say that one should not seek hiddur; on the contrary, whoever can beautify a mitzvah and spend money on mitzvot, would that he do so! And since we have become a generation that embellishes the exterior, seeking Italian parquet flooring for the living room, it is certainly fitting that one also seek a mehudar etrog. The point is merely that we have become a generation fixated on the external aspects of mitzvot rather than their inner essence.
It is told of the Vilna Gaon that robbers once broke into his house, and the disciples in the outer room were terrified. The Gra, hearing the commotion, came out, and as soon as the robbers saw him, they fled. The disciples asked him: "Rebbe, what was that - a miracle? A supernatural wonder?" He said to them: "Not a wonder or anything of the sort; I am simply wearing tefillin, and it is written, 'And all the peoples of the earth shall see that the name of Hashem is called upon you, and they shall be afraid of you,' and Chazal taught: this refers to the tefillin of the head." They said to him: "We are also wearing tefillin!" He replied: "The text says tefillin in the head (תפילין שבראש), not tefillin on the head. Do you understand the difference? How much of the tefillin is inside your head, rather than merely a box placed on top?" There has never been a generation with so many hiddurim in tefillin as ours. Look at photographs of tefillin from fifty or a hundred years ago - not military-issue tefillin that look like folded cardboard, but genuine handcrafted tefillin - was there such a level of squareness, of precision in the spacing of the compartments? You will not find it. And are we better than them? Where are we compared to them! For them, the tefillin were inside the head, in devotion and in holiness.
And this is what the Holy One, blessed be He, is saying here: they pursue asceticism, piety, and holiness, clinging to all sorts of stringencies and protective fences - why? Because it feels rewarding, giving the sense that you have achieved something. Yet at that very moment, a person abandons everything behind him: the core laws, halachot, and fundamental requirements. How careful are you with guarding your eyes, guarding your tongue, and treating your fellow man properly? Yet what is he meticulous about? He once read that there is a special practice to do things in a very specific way, and that is what he insists on.
Someone who was completely "religious lite" once came to ask whether one is permitted to go to the beach during the Nine Days. And his question was about a mixed beach! Notice the irony: where is basic modesty, where is concern for clear Torah prohibitions at every moment? In truth, the entire matter of going to the beach during this period has no explicit halachic prohibition. Some say that bathing in cold water is forbidden, and according to their view bathing in the sea is also prohibited for that reason, but regarding the general customs of the Three Weeks, there is no such baseline law. Yet here he was, seeking a stringency on that matter, while a mixed beach did not bother him at all. This reflects our reality on a smaller scale: people latch onto stringencies and peripheral matters, while completely forgetting and abandoning the core halachah. That is why the Holy One, blessed be He, says: first justice, then righteousness, and only then do they desire closeness to God, which represents higher spiritual levels.
There is a story of a chassid who came to his Rebbe and said that he wanted to attain Ruach HaKodesh (divine inspiration). The Rebbe told him: fast for forty days, then roll in the snow, sleep on the bare ground, and then with God's help you will merit Ruach HaKodesh. The man followed the recipe exactly, returned to his Rebbe, and said: Rebbe, I waited and waited, and nothing happened. The Rebbe brought him over to the window and said to him: do you see that tzaddik out there? He answered: no. The Rebbe asked: do you not see the horse lying there? He replied: that I do see. The Rebbe said to him: do you know how many fasts that horse observes? Entire days pass where his master brings him food only at night. And rolling in the snow - how many times have I seen him roll in the snow! He always sleeps only on the ground. And he observes a taanit dibur (fast of speech) his entire life; he has never spoken lashon hara. A person can do all of these things and still remain a horse. One of the great Torah leaders remarked: where is the true test? When the fast ends, how do you approach your food? That is where one sees whether a person remained a horse or acquired a true spiritual quality and attained something in holiness. This is a piercing rebuke, meant not just for others but for oneself to take to heart. We must recognize that our generation is one of external appearances. People focus on how someone looks on the outside, what impression he makes; never mind what he actually does, as long as he wears the suit and hat.
Rabbi Abutbul once pointed out a distressing reality, an unfortunate distortion in our community regarding head coverings. A woman who wears a sheitel (wig) is often perceived as more modest and righteous than one who wears a cloth head covering; her children will be accepted into a seminary while the other's will not, simply because she wears a scarf. It is truly an upside-down world. Similarly, at the time of the controversy over Indian wigs, Rabbi Ratzabi sent a letter to one of the leading rabbis: we had a heaven-sent opportunity when women went for several weeks without wigs, wearing only cloth head coverings, but immediately a rabbi arose and rushed to issue a permit, claiming overseers had been sent and everything was fine. He wrote to him: Ribbono Shel Olam, we had such an opportunity to uproot this terrible falsehood! A head covering is meant to cultivate modesty, yet it is replaced with a wig - and how many of these wigs are truly modest? Even those authorities who originally permitted wigs, what kind were they discussing? There are those who noted that the term "pe'ah nochrit" (foreign wig) implies that it can make a woman look like a stranger. But what can one say, and to whom is there to talk? We live in an age of external appearances, a generation that does everything for outward show. When it comes to inwardness, something that demands sacrifice and self-overcoming, the generation is weak. May Hashem grant us merit and deliver us from every manner of sin and iniquity.
לָמָּה צַּמְנוּ וְלֹא רָאִיתָ עִנִּינוּ נַפְשֵׁנוּ וְלֹא תֵדָע הֵן בְּיוֹם צֹמְכֶם תִּמְצְאוּ־חֵפֶץ וְכָל־עַצְּבֵיכֶם תִּנְגֹּשׂוּ׃ - "Why have we fasted and You did not see? Why have we afflicted our souls and You take no note?" Behold, on the day of your fast you pursue your business, and exact all your debts.
The people complain against the prophet and against Heaven: why do we fast while You, Master of the Universe, do not look upon our fasting and do not accept our prayers? "Why have we afflicted our souls and You take no note?" - as if You act as though You do not know and do not pay attention to us; enemies rule over us while You seemingly ignore our plight; we have fasted, yet we do not see You delivering us.
The prophet answers them: "Behold, on the day of your fast you pursue your business, and exact all your debts." I see that the outcome of your fast is strife. How so? On a fast day, everyone gathers in the city square to pray, and a person finds an opportunity: so-and-so has owed me money for a long time, it is good that I ran into him now! Thus, the fast day, which is meant to be a day of rectifying deeds and improving character traits, turns into a day of quarrels, with each person confronting his fellow and settling scores. This is the meaning of "on the day of your fast you pursue your business" - on the fast day you seek to advance your personal affairs and achieve your interests. And if he does not pay you, "and exact all your debts," using the language of negishah (exacting pressure), one who forcibly demands his debt and does not let the debtor escape, as in "you shall not be to him like a creditor [nosheh]."
"Atzveichem" (your debts/labors) refers to your money, and why is money called etzev (grief or toil)? Radak explains that money is acquired through a person's toil and sorrow. What brings sorrow to a person? Money. The endless pursuit of it, and once it is acquired, the worry over how to preserve it; and if one has investments, he is under constant stress: how is the stock market doing, did it go up, did it go down? It turns out that much of a person's sadness and anxiety stems from money.
A story is told of a king whose son fell into a deep melancholy. The doctors told him that he must find a happy man and wear his shirt, and this would cure him of his sadness. The king sent emissaries throughout his kingdom to search for a truly happy man. They scaled mountains and traversed valleys, visiting cities and towns, but found no one. They would ask: "Are you happy?" and the reply was: "Me? If only; I wish." One day, when they had already grown despondent, they noticed a shepherd sitting on a stone, leaning against a tree, his flock grazing peacefully before him while he played his flute with pure joy. They approached him and asked: "Are you happy?" He said: "Yes, Baruch Hashem." They said to him: "Do us a favor; the king's son is ill, please give us your shirt." He replied: "Gladly, but I do not have a shirt." They said: "You do not have a shirt?" He told them: "If I had a shirt, I would no longer be happy. I would have to worry that it might tear, wash it, and guard it. I am happy precisely because I have nothing, and nothing troubles me. What could you take from me, my flute? I can carve another one tomorrow." Such is reality: one who increases possessions increases worry. Therefore, "and exact all your debts" - you exploit the fast day to demand your money and press your fellow men.
The Malbim explains that after stating in the previous verse that all their seeking of Hashem is superficial and that they do not truly desire closeness to Him, the prophet adds here that not only is this the case, but they even come to dispute why Hashem does not answer their prayer. They consider themselves righteous and present claims and grievances before Him.
Now, the word tzom ("fast") at its root does not mean abstaining from food (ta'anit), as we explained in the name of the Radak and as the Malbim likewise explains. Proof of this comes from the verse itself: "Why have we fasted and You have not seen; why have we afflicted our soul and You do not know?" - for fasting (tzom) and self-affliction (inuy) are two separate matters. Tzom denotes gathering and binding together, like tzomet hagidim (the junction of the sinews), a place where many sinews converge; like tzamah (a braid), tying many hairs together; and likewise, "from behind your veil (tzamatech)" (Shir HaShirim 4:1), and "the snare (tzamim) shall hold fast upon him" (Iyov 18:9) - all of which convey concentrating, gathering, and condensing many elements into one point. Whenever they wished to hold a public gathering over a drought or any distress, they would "declare a fast (tzom)": they would gather all the people into the city square, pray, recite Avinu Malkeinu, and do whatever was necessary. Generally, on that same day, they would also abstain from eating, and from this, the word tzom came to denote a day of fasting.
Thus, two distinct processes are at work here. The purpose of the assembly (tzom) is to examine one's deeds, as we learned in the Mishnah in Tractate Ta'anit, where they would gather on a fast day and the Beit Din would sit to investigate what required rectification and what corrupt practices existed. How sorely this is missed in our generation - that people would gather and strive to improve! This is the tzom: rectification for the future. Self-affliction (inuy), on the other hand, is the abstention from food and physical pleasure: rectification for the past. When a person commits a sin, his body experiences pleasure; when he afflicts himself, he strips away bodily desires and physical pleasures, measure for measure: the indulgence I gave my body is rectified through the physical distress I now endure.
Therefore, regarding the tzom (the public assembly) they say, "and You have not seen," whereas regarding the affliction (the inner abstention) they say, "and You do not know." An assembly is an open, visible event; anyone can see that we have gathered and that we are discussing communal improvement. But what is the true purpose of your fasting? Is it merely a diet? Are you fasting simply because everyone else is fasting? Or does the abstention stem genuinely from remorse over the past? That, only the Searcher of hearts and minds can know. Therefore they argue: "We afflicted our souls and You do not know" - are You not the Searcher of hearts and minds, able to see that our intention is to repent fully for all we have done in the past?
And the Holy One, blessed be He, answers them: "Behold, on the day of your fast you pursue your desires." A fast and day of affliction must come whole-heartedly, with a person casting aside all physical pleasures and lusts, so that his sole purpose is for Hashem alone. You, however, seek to gratify your hearts' desires even on the fast day. Take an extreme example: there are people who spend the entire fast day shopping. Why? Planning how to break the fast! All day long, they are preoccupied with what food to prepare, what dishes to serve, what to eat first and what to eat next. What kind of fast is that? On a fast, you ought to feel revulsion toward physical indulgence and have no desire for it at all, yet on this very day, you crave and pursue all your worldly desires.
"And all your sorrows you exact" - and the Malbim offers a wonderful explanation: the sorrow (etzev) you experience on this day from having to withdraw from worldly pursuits. It cannot be denied, after all; the person did not eat today. Yet the mere fact that he did not eat was not done with a willing spirit; rather, "you exact" (tingosu) - you force yourself, coerce yourself, doing it under compulsion and strain, like someone who has no choice. The fast is a heavy burden to you, and you are only looking for when it will finally end. Could the Holy One, blessed be He, possibly desire a fast like that?
הֵן לְרִיב וּמַצָּה תָּצוּמוּ וּלְהַכּוֹת בְּאֶגְרֹף רֶשַׁע לֹא־תָצוּמוּ כַיּוֹם לְהַשְׁמִיעַ בַּמָּרוֹם קוֹלְכֶם׃ - Behold, you fast for strife and contention, and to strike with the fist of wickedness; you do not fast as on this day, to make your voice heard on high.
Your fast is for strife and contention; how could I desire such a fast? "And to strike with the fist of wickedness" - in the sense of strongmen using brute force, striking those who owe you money, as the Radak explains: you exploit the fast day to oppress your fellows and demand your debts, taking advantage of the opportunity when you encounter the debtor on the fast day. "You do not fast as on this day" - the Radak explains: you fast as though I do not see you, and the phrase kayom ("as on this day") is like "Swear to me this day" (Bereishit 25:31). "To make your voice heard on high" - you scream in your prayers as if pouring out your souls before Me. Is that why you fast, merely so that Hashem should note that you cried out, without any inward change?
The Malbim explains according to his consistent approach that "you fast" (tatzumu) here also denotes assembling and gathering many together in one place. In order to evaluate how reluctant your assembly for Heaven's sake truly is, compare it to your other gatherings. You have assemblies for strife and contention, to quarrel with someone; you have assemblies to strike with a wicked fist, to take vengeance upon whoever you think deserves it. At those gatherings, we see you coming with joy and enthusiasm, assembling eagerly. The prophet says to them: "You do not fast as on this day to make your voice heard on high" - you do not gather to raise your voice to Heaven the way you gather for strife and contention. To those assemblies you come with joy, whereas on this day, when you gather to afflict your souls, there is such distress and resentment, such misery, and you are only looking for a way to relieve the burden.
This is common enough: if the chazzan elongates his prayers just a little, people start dropping hints: "May our prayer quickly be accepted with favor!" When he reaches Avinu Malkeinu, they shout, "Have mercy!" rushing him along: Come on already, when does the fast end? Do not trap us here for another five minutes! There are elderly people here! Not for my sake, Heaven forbid, I am willing to fast another whole day! And outside, he barely gives those elderly people a second thought. There are people who, out of all the laws of the synagogue, only know the laws of torech tzibbur (burdening the congregation) - that is all they know!
The Malbim adds that this applies to the affliction as well. We noted that affliction is meant as rectification for the past, yet your affliction is not genuine because it is purely external. Were you truly intending to rectify the past, you would effect an internal change, whereas you make only an outward show, appearing as if you are afflicting yourselves. "You do not fast as on this day to make your voice heard on high" - you do not fast to make your voice heard in Heaven, but merely to show people that you are fasting; everything is superficial, done solely for impression. To this the Holy One, blessed be He, declares: I do not want such a fast. I want a fast accompanied by internal transformation, remorse for the past, and a firm resolution for the future. A fast that is entirely external show and posturing is not what I desire.
Chapter 58 opens with a command to the prophet to cry aloud from the throat with an ever-increasing voice, like a shofar which has no voice of its own other than the breath blown into it, and to rouse the people to repentance: "To My people" for transgressions between man and God, and "to the house of Jacob" for those between man and his fellow. The primary sin is an externalized service of Hashem: they seek Hashem daily, desiring to know His ways and draw near to God, but it is all lip service rather than deed, skipping the proper ladder of progression - first justice, then righteousness, and only then closeness to God. When their prayers are not answered, they complain, "Why have we fasted, and You did not see?" The prophet replies that both fasting, which is meant for introspection to rectify the future, and affliction, which is meant to rectify the past, are performed by them through coercion and oppression, and are exploited for strife and monetary demands. From this comes the moral lesson for our generation, an age of superficiality and instant gratification, which beautifies the outer shell while forgetting the core requirement: it is not the box on the head that is required, but the tefillin inside the mind; not the external impression, but the internal transformation of the heart.