The Sefer HaChinukh explains the mitzvah of confession and repentance, stressing that verbal expression makes a person's inner regret concrete and helps produce lasting change. It also discusses the restorative and educational purpose of the commandment.
מִצְוַת וִדּוּי עַל הַחֵטְא – שֶׁנִּצְטַוִּינוּ לְהִתְוַדּוֹת לִפְנֵי הַשֵּׁם עַל כָּל הַחֲטָאִים שֶׁחָטָאנוּ בְּעֵת שֶׁנִּתְנַחֵם עֲלֵיהֶן, וְזֶהוּ עִנְיַן הַוִּדּוּי שֶׁיֹּאמַר הָאָדָם בְּעֵת הַתְּשׁוּבָה אָנָּא הַשֵּׁם חָטָאתִי, עָוִיתִי וּפָשַׁעְתִּי כָּךְ וְכָךְ. כְּלוֹמַר שֶׁיַּזְכִּיר הַחֵטְא שֶׁעָשָׂה בְּפֵרוּשׁ בְּפִיו. וִיבַקֵּשׁ כַּפָּרָה עָלָיו וְיַאֲרִיךְ בַּדָּבָר כְּפִי מַה שֶׁיִּהְיֶה צַחוּת לְשׁוֹנוֹ. וְאָמְרוּ זִכְרוֹנָם לִבְרָכָה, שֶׁאֲפִלּוּ הַחֲטָאִים שֶׁחִיְּבָה הַתּוֹרָה קָרְבָּן עֲלֵיהֶם, צָרִיךְ הָאָדָם אֶל הַוִּדּוּי עִם הַקָּרְבָּן, וְעַל זֶה נֶאֱמַר (במדבר ה ו) דַּבֵּר אֶל בְּנֵי יִשְׂרָאֵל אִישׁ אוֹ אִשָּׁה כִּי יַעֲשׂוּ מִכָּל חַטֹּאת הָאָדָם לִמְעֹל מַעַל בַּיי וְאָשְׁמָה הַנֶּפֶשׁ הַהִיא וְהִתְוַדּוּ אֶת חַטָּאתָם אֲשֶׁר עָשׂוּ. וְאָמְרוּ בַּמְּכִילְתָּא (ספרי זוטא כאן) לְפִי שֶׁנֶּאֱמַר (ויקרא ה ה) וְהִתְוַדָּה אֲשֶׁר חָטָא, יִתְוַדֶּה עַל חֵטְא שֶׁחָטָא עָלֶיהָ, עַל חַטָּאת כְּשֶׁהִיא קַיֶּמֶת, לֹא מִשֶּׁנִּשְׁחֲטָה, כְּלוֹמַר בְּעוֹד שֶׁבֶּהֱמַת הַקָּרְבָּן חַיָּה, וְלֹא מִשֶּׁנִּשְׁחֲטָה. וְעוֹד אָמְרוּ שָׁם לָמַדְנוּ חִיּוּב הַוִּדּוּי לִמְטַמֵּא מִקְדָּשׁ וְקָדָשָׁיו, מִנַּיִן אַתָּה מַרְבֶּה שְׁאָר כָּל הַמִּצְוֹת, כְּלוֹמַר שֶׁהַמִּקְרָא הַזֶּה בָּא בְּפָרָשַׁת וַיִּקְרָא בִּמְטַמֵּא מִקְדָּשׁ וְקָדָשָׁיו, מִנַּיִן אַתָּה מְרַבֶּה שְׁאָר כָּל הַמִּצְוֹת? דִּכְתִיב דַּבֵּר אֶל בְּנֵי יִשְׂרָאֵל וְגוֹ' וְהִתְוַדּוּ. כְּלוֹמַר, שֶׁנִּדְרָשׁ הַכָּתוּב כְּאִלּוּ לֹא נִכְתַּב עַל דָּבָר מְיֻחָד. וּמִנַּיִן שֶׁיֵּשׁ בַּמַּשְׁמָע הַזֶּה אַף מִיתוֹת וְכָרֵתוֹת? שֶׁנֶּאֱמַר גַּבֵּי וִדּוּי אַהֲרֹן בְּאַחֲרֵי מוֹת (שם טז טז) לְכָל חַטֹּאתָם. וְדָרְשׁוּ זִכְרוֹנָם לִבְרָכָה לְרַבּוֹת מִצְוֹת לֹא תַעֲשֶׂה, וְכִי יַעֲשׂוּ דִּכְתִיב כָּאן לְרַבּוֹת מִצְוֹת עֲשֵׂה, כְּלוֹמַר, אִם בִּטֵּל מִצְוַת עֲשֵׂה שֶׁהָיָה יָכוֹל לַעֲשׂוֹת שֶׁחַיָּב לְהִתְוַדּוֹת עָלֶיהָ. וְעוֹד דָּרְשׁוּ שָׁם בַּמְּכִילְתָּא מִכָּל חַטֹּאת הָאָדָם, מִמָּה שֶׁבֵּינוֹ לְבֵין חֲבֵרוֹ עַל הַגְּנֵבוֹת וְעַל הַגְּזֵלוֹת וְעַל לָשׁוֹן הָרַע, וְזֶה הַוִּדּוּי, צָרִיךְ בֶּאֱמֶת שֶׁיָּשִׁיב הֶחָמָס אֲשֶׁר בְּכַפָּיו, שֶׁאִם לֹא כֵּן מוּטָב שֶׁלֹּא יִתְוַדֶּה עַל זֶה. לִמְעֹל מַעַל לְרַבּוֹת כָּל חַיָּבֵי מִיתוֹת שֶׁיִּתְוַדּוּ. יָכוֹל אַף הַנֶּהֱרָגִין עַל פִּי זוֹמְמִין, כְּלוֹמַר אַף עַל פִּי שֶׁהוּא יוֹדֵעַ שֶׁלֹּא חָטָא, אֶלָּא שֶׁהוּעַד עָלָיו עֵדוּת שֶׁקֶר, שֶׁיְּהֵא חַיָּב לְהִתְוַדּוֹת עַל זֶה? תַּלְמוּד לוֹמַר וְאָשְׁמָה הַנֶּפֶשׁ, לֹא אָמַרְתִּי אֶלָּא כְּשֶׁיִּהְיֶה שָׁם אַשְׁמָה, אֲבָל לֹא כְּשֶׁיֵּדַע שֶׁאֵין לוֹ חֵטְא אֶלָּא שֶׁהוּעַד שֶׁקֶר עָלָיו. הִנֵּה הִתְבָּאֵר שֶׁכָּל הָעֲוֹנוֹת הַגְּדוֹלִים וְהַקְּטַנִּים וַאֲפִלּוּ מִצְוֹת עֲשֵׂה חַיָּב הָאָדָם עֲלֵיהֶם הַוִּדּוּי. וּלְפִי שֶׁבָּאָה מִצְוָה זוֹ שֶׁל וִדּוּי עִם חִיּוּב הַקָּרְבָּן, כְּמוֹ שֶׁכָּתוּב בְּפָרָשַׁת וַיִּקְרָא דִּכְתִיב שָׁם (ה ו) וְהֵבִיא אֶת אֲשָׁמוֹ וְגוֹ, שֶׁמָּא יַעֲלֶה בְּמַחֲשָׁבָה שֶׁאֵין הַוִּדּוּי לְבַדּוֹ מִצְוָה בִּפְנֵי עַצְמָהּ, אֶלָּא מֵהַדְּבָרִים הַנִּגְרָרִים אַחַר הַקָּרְבָּן, עַל כֵּן הָיוּ צְרִיכִים לְבָאֵר בַּמְּכִילְתָּא שֶׁאֵינוֹ כֵּן, אֶלָּא מִצְוָה בִּפְנֵי עַצְמָהּ הִיא. וְכֵן אָמְרוּ שָׁם יָכוֹל בִּזְמַן שֶׁהֵם מְבִיאִין מִתְוַדִּין, וּמִנַּיִן אַף בִּזְמַן שֶׁאֵין מְבִיאִין, שֶׁנֶּאֱמַר בְּנֵי יִשְׂרָאֵל וְהִתְוַדּוּ. כְּלוֹמַר שֶׁהַקַּבָּלָה בָּאָה לִדְרֹשׁ כֵּן. וַעֲדַיִן הָיִיתִי אוֹמֵר, שֶׁאֵין הַוִּדּוּי אֶלָּא בָּאָרֶץ, כְּלוֹמַר אַף עַל פִּי שֶׁמִּתְוַדִּין בְּלֹא קָרְבָּן, מִכָּל מָקוֹם שֶׁלֹּא יִהְיֶה חִיּוּב הַוִּדּוּי אֶלָּא בָּאָרֶץ, כִּי שָׁם עִקַּר הַכַּפָּרָה, וְשָׁם הַקָּרְבָּנוֹת, וְעִקַּר הַכֹּל בָּהּ. מִנַּיִן אַף בַּגָּלוּיוֹת? דִּכְתִיב (שם כו מ) וְהִתְוַדּוּ אֶת עֲוֹנָם וְאֶת עֲוֹן אֲבֹתָם. כְּלוֹמַר עֲוֹן אֲבוֹתָם שֶׁחָטְאוּ וְגֹרְשׁוּ מִן הָאָרֶץ. וְכֵן אָמַר דָּנִיֵּאל בְּחוּצָה לָאָרֶץ (ט ז) לְךָ יְיָ הַצְּדָקָה וְלָנוּ בֹּשֶׁת הַפָּנִים כַּיּוֹם הַזֶּה. הִנֵּה הִתְבָּאֵר שֶׁהַוִּדּוּי מִצְוָה בִּפְנֵי עַצְמָהּ, וְנוֹהֵג בְּכָל מָקוֹם. וְאָמְרוּ גַּם כֵּן בַּסִּפְרָא (אחרי ד ו) וְהִתְוַדָּה זֶה וִדּוּי דְּבָרִים. מִדִּינֵי הַמִּצְוָה. מָה שֶׁאָמְרוּ זִכְרוֹנָם לִבְרָכָה (תענית טז, א) שֶׁהַתְּשׁוּבָה הִיא שֶׁיַּעֲזֹב הַחוֹטֵא חֶטְאוֹ וִיסִירֶנּוּ מִלִּבּוֹ וּמִמַּחְשַׁבְתּוֹ וְיִגְמֹר בְּלִבּוֹ שֶׁלֹּא יַעֲשֶׂה כֵן עוֹד. כְּדִכְתִיב (ישעיהו נה ז) יַעֲזֹב רָשָׁע דַּרְכּוֹ וְאִישׁ אָוֶן מַחְשְׁבֹתָיו. וְאַחַר כָּךְ יִתְוַדֶּה עָלָיו. כְּלוֹמַר שֶׁיֹּאמַר דִּבְרֵי הַתְּשׁוּבָה בְּפִיו, שֶׁנֶּאֱמַר (שמות לב לא) וַיַּעֲשׂוּ לָהֶם אֱלֹהֵי זָהָב. וְגַם כֵּן צָרִיךְ לְהַזְכִּיר בְּפֵרוּשׁ שֶׁלֹּא יָשׁוּב לַעֲשׂוֹת הַחֵטְא עוֹד, שֶׁנֶּאֱמַר (הושע יד ד) וְלֹא נֹאמַר עוֹד אֱלֹהֵינוּ לְמַעֲשֵׂה יָדֵינוּ וְגוֹ'. וְאָמְרוּ זִכְרוֹנָם לִבְרָכָה (עי' רמב"ם הל' תשובה פ"א הל"ב), שֶׁשָּׂעִיר הַמִּשְׁתַּלֵּחַ הָיָה מְכַפֵּר כְּשֶׁעָשָׂה תְּשׁוּבָה עַל כָּל עֲבֵרוֹת שֶׁבַּתּוֹרָה הַקַּלּוֹת וְהַחֲמוּרוֹת, בֵּין שֶׁעָבַר עֲלֵיהֶן בְּזָדוֹן אוֹ בִּשְׁגָגָה, בֵּין שֶׁהוֹדַע לוֹ אוֹ לֹא הוֹדַע לוֹ, אֲבָל אִם לֹא עָשָׂה תְּשׁוּבָה אֵין שָׂעִיר הַמִּשְׁתַּלֵּחַ מְכַפֵּר אֶלָּא עַל הַקַּלּוֹת. וּמַה הֵן הַקַּלּוֹת וּמַה הֵן הַחֲמוּרוֹת? עֲבֵרוֹת שֶׁחַיָּבִין עֲלֵיהֶן מִיתַת בֵּית דִּין אוֹ כָּרֵת, וְכֵן שְׁבוּעַת שָׁוְא וְשֶׁקֶר, אַף עַל פִּי שֶׁאֵין בָּהֶם כָּרֵת מִן הַחֲמוּרוֹת הֵן, וּשְׁאָר מִצְוֹת עֲשֵׂה וְלֹא תַעֲשֶׂה שֶׁאֵין בָּהֶם כָּרֵת נִקְרָאוֹת קַלּוֹת כְּנֶגֶד הַחֲמוּרוֹת. וְעַכְשָׁו בַּעֲוֹנֹתֵינוּ שֶׁאֵין לָנוּ מִקְדָּשׁ, וְלֹא מִזְבֵּחַ כַּפָּרָה אֵין לָנוּ אֶלָּא תְּשׁוּבָה, וְהַתְּשׁוּבָה מְכַפֶּרֶת עַל כָּל הָעֲבֵרוֹת, וַאֲפִלּוּ הָיָה רָשָׁע גָּמוּר כָּל יָמָיו וְעָשָׂה תְּשׁוּבָה שְׁלֵמָה בָּאַחֲרוֹנָה אֵין מַזְכִּירִין לוֹ שׁוּם רִשְׁעוֹ, שֶׁנֶּאֱמַר (יחזקאל לג יב) וְרִשְׁעַת הָרָשָׁע לֹא יִכָּשֶׁל בָּהּ בְּיוֹם שׁוּבוֹ מֵרִשְׁעוֹ וְגוֹ'. בַּמֶּה דְבָרִים אֲמוּרִים שֶׁהַתְּשׁוּבָה לְבַדָּהּ מַסְפֶּקֶת בַּעֲבֵרוֹת שֶׁבֵּין אָדָם לַמָּקוֹם, כְּגוֹן הָאוֹכֵל דָּבָר אָסוּר אוֹ בּוֹעֵל בְּעִילָה אֲסוּרָה, וְכֵן הַמְבַטֵּל אַחַת מִמִּצְוֹת עֲשֵׂה וְכַיּוֹצֵא בָּזֶה, אֲבָל עֲבֵרוֹת שֶׁבֵּין אָדָם לַחֲבֵרוֹ, כְּגוֹן הַחוֹבֵל בַּחֲבֵרוֹ, אוֹ הַגּוֹזֵל מָמוֹנוֹ, אוֹ בְּכָל דָּבָר אַחֵר שֶׁהִזִּיקוֹ שֶׁלֹּא כַּדִּין בֵּין בְּמַעֲשֶׂה בֵּין בְּדִבּוּר, אֵין נִמְחָל לוֹ לְעוֹלָם בִּתְשׁוּבָה בִּלְבַד, עַד שֶׁיִּתֵּן לַחֲבֵרוֹ מַה שֶּׁהוּא חַיָּב לוֹ וְעַד שֶׁיְּרַצֵּהוּ, וְאִם לֹא רָצָה חֲבֵרוֹ לְהִתְרַצּוֹת לוֹ כְּבָר אָמְרוּ זִכְרוֹנָם לִבְרָכָה (יומא פז א), מָה תַּקָּנָתוֹ. וּמֵעִנְיַן הַמִּצְוָה כְּמוֹ כֵן, מָה שֶׁאָמְרוּ בַּתּוֹסֶפְתָּא, שֶׁעֶשְׂרִים וְאַרְבָּעָה דְּבָרִים הֵם שֶׁמְּעַכְּבִין אֶת הַתְּשׁוּבָה, וְשָׁם מָנוּ אוֹתָן חֲכָמִים. וְיֶתֶר פְּרָטֵי הַמִּצְוָה יִתְבָּאֲרוּ בְּפֶרֶק אַחֲרוֹן מִיּוֹמָא [הלכות תשובה פ"א].
The commandment of confession of sin: We are commanded to confess before God our sins that we have sinned, at such time that we feel remorse for them. And this is the content of confession: to say at the time of repentance, “Please, God, I have sinned, I have transgressed, I have rebelled [in] such and such,” meaning to say that he mention the sin that he did explicitly with his mouth. He should [then] seek atonement for it and extend his words in this matter according to his fluency. And they, may their memory be blessed, said that even sins that require the bringing of a sin-offering still demand confession with the offering, and about this it states (Numbers 5:6), “Speak to the children of Israel [saying], a man or woman who commits from any of the sins of man and rebels against the Lord, that soul is guilty and they shall confess the sins that they did.” [The Sages] said in the Mekhilta (Sifrei Zuta on Numbers 5:6), “Since it says ‘confess the sin’ (Leviticus 5:5) it means that the sin must be extant, that is that the sin-offering is alive and not slaughtered.” This means that the animal to be offered must still be alive. They also said there, “We see that one must confess if he renders impure the Temple and its holy things. From where do you know to include all other commandments?” That is that this verse in Parashat Vayikra only [discusses] one who renders impure the Temple and its holy things; from where do you know to include all other commandments? “As it is written, ‘Speak to the children of Israel, etc. and they should confess.’” That is, that we expound the verse as if it is not written about a specific thing. “And from where do we know that its understanding [includes sins that are punishable by] death and excision? Since it is stated about the confession of Aharon in Acharei Mot (Leviticus 16:16) ‘for all their sins.’” [The Sages], may their memory be blessed, expounded [on this verse] to include negative commandments; and “that they did” which is written here to include positive commandments, meaning to say that if he does not do a positive commandment that he could have done, he is obligated to confess about it. And they further expounded there in the Mekhilta, “‘From any of the sins of man’ — from that which is between him and his fellow: theft, robbery and evil speech.” And this confession truthfully requires that he return the “[theft] that is in his hands,” as if he does not do so it would be better not to confess about it. “‘To rebel’ includes all those sentenced to death who must [also] confess. I might have thought to include even those convicted by false witnesses”; that is, even though he knows that he did not sin, except that false testimony was testified against him, that he be obligated to confess about this. “Hence the verse teaches, ‘soul [that] is guilty’ — I only said when there is guilt there, but not when he knows that he did not sin, except false testimony was testified against him. Hence we understand that [for] all iniquities, large and small — even positive commandments — a man is obligated to confess about them. And since this commandment of confession comes with the obligation to bring an offering — as is written in Parashat Vayikra there (Leviticus 5:6), “And he shall bring his guilt-offering, etc.” — one might think that the confession is not an independent commandment on its own, but rather only one of the things that are an extension of the sacrifice. Therefore they had to elucidate in the Mekhilta that such is not the case, but rather it is indeed an independent commandment. And so they said there, “I might have thought that I only confess when they brought [offerings]. From where do I know even at the time that they do not bring [them]? Since it is stated, ‘the children of Israel[...] and they shall confess’” — meaning to say that the tradition comes to expound [it] in this way. “Still, I might have thought that there is confession only in the Land”; that is, even though one may confess without the sacrifice, nonetheless, that the obligation for confession is only in the Land, as that is the locus of atonement, and the sacrifices are there and the locus of everything is there. “From where do I know to include the Diaspora? From that which is written (Leviticus 26:40), ‘And they shall confess their iniquity and the iniquity of their fathers.’” That is, the iniquity of their fathers who sinned and were exiled from the Land. “And so [too,] did Daniel say outside of the Land (Daniel 9:7) ‘For You, Lord, is the righteousness and for us is the shame on this day.’” Hence it is elucidated that confession is an independent commandment and that it is practiced in all places. And they also said in the Sifra (Sifra, Acharei Mot, Section 4:6), “‘And they shall confess’ — that is verbal confession.” From the laws of the commandment is that which they, may their memory be blessed, said (Taanit 15a) that repentance is that the sinner leave the sin and remove it from his heart and from his thought, and he decide in his heart not to do like this again, as it is written (Isaiah 55:7), “Let the wicked give up his way, the sinful man his thoughts”; and afterwards, he must confess about it, meaning to say that he say the words of repentance orally, as it is stated (Exodus 32:31), “and they made for themselves a god of gold.” And he must also mention explicitly that he will not return to do the sin again, as it is stated (Hosea 14:4), “and we will not again say ‘our god’ about the work of our hands, etc.” And they, may their memory be blessed, said (see Rambam, Mishneh Torah, Laws of Repentance 1:2) that the scapegoat would atone for all sins when one repented, light and weighty — whether he transgressed them volitionally or accidentally whether it was known to him or unknown to him. But if he did not repent, the scapegoat only atones for the light ones. And what are the light ones and what are the weighty ones? [Weighty ones] are sins for which one is liable for the death penalties of the court or excision; and also vain and false oaths are from the weighty ones, even though they do not come with excision. And the other positive and negative commandments that do not come with excision are called light, in comparison to the weighty ones. And now that we do not have the Temple and the altar of atonement, on account of our iniquities, we only have repentance. And repentance atones for all sins. And even if one was a complete evildoer all of his days and he repented completely at the end, we do not mention any of his evil, as it is stated (Ezekiel 33:12), “and the wickedness of the wicked will not cause him to stumble when he turns back from his wickedness, etc.” To what do these words apply that repentance alone suffices? To sins between man and the Omnipresent, such as one who eats something prohibited or has a prohibited sexual intercourse and so [too,] one who negates one of the positive commandments and similar to it. But [regarding] sins between a man and his fellow, such as one who injures his fellow, or robs his money or with any other thing through which he illegally injures him — whether in action or in speech — it is never forgiven him with repentance alone, until he gives his fellow what he owes him and until he is appeased. And they, may their memory be blessed, have already said (Yoma 87a) what is his remedy if his fellow does not want to be appeased by him. And also from the content of the commandment is that which they said in the Tosefta that there are twenty-four things that impede repentance, and they enumerate them there. [This] and the rest of the details of the commandment are elucidated in the last chapter of Yoma. (See Mishneh Torah, Laws of Repentance 1.)