Rabbeinu Yonah lays out repentance as a step-by-step spiritual process beginning with recognition of wrongdoing and fear of consequences. He emphasizes brokenheartedness, confession, and corrective action.
הַשַּׁעַר הָרִאשׁוֹן – בְּבֵאוּר הַתְּשׁוּבָה וְעִקָּרֶיהָ. מִן הַטּוֹבוֹת אֲשֶׁר הֵיטִיב הַשֵּׁם יִתְבָּרַךְ עִם בְּרוּאָיו, כִּי הֵכִין לָהֶם הַדֶּרֶךְ לַעֲלוֹת מִתּוֹךְ פַּחַת מַעֲשֵׂיהֶם וְלָנוּס מִפַּח פִּשְׁעֵיהֶם, לַחְשֹׂךְ נַפְשָׁם מִנִּי שַׁחַת וּלְהָשִׁיב מֵעֲלֵיהֶם אַפּוֹ, וְלִמְּדָם וְהִזְהִירָם לָשׁוּב אֵלָיו כִּי יֶחֶטְאוּ לוֹ, לְרֹב טוּבוֹ וְיָשְׁרוֹ כִּי הוּא יָדַע יִצְרָם, שֶׁנֶּאֱמַר (תהלים כה, ח): "טוֹב וְיָשָׁר ה' עַל כֵּן יוֹרֶה חַטָּאִים בַּדָּרֶךְ", וְאִם הִרְבּוּ לִפְשֹׁעַ וְלִמְרוֹד וּבֶגֶד בּוֹגְדִים בָּגָדוּ, לֹא סָגַר בַּעֲדָם דַּלְתֵי תְּשׁוּבָה, שֶׁנֶּאֱמַר (ישעיה לא, ו): "שׁוּבוּ לַאֲשֶׁר הֶעְמִיקוּ סָרָה". וְנֶאֱמַר (ירמיה ג, כב): "שׁוּבוּ בָּנִים שׁוֹבָבִים אֶרְפָּה מְשׁוּבֹתֵיכֶם". וְהֻזְהַרְנוּ עַל הַתְּשׁוּבָה בְּכַמָּה מְקוֹמוֹת בַּתּוֹרָה, וְהִתְבָּאֵר, כִּי הַתְּשׁוּבָה מְקֻבֶּלֶת גַּם כִּי יָשׁוּב הַחוֹטֵא מֵרֹב צָרוֹתָיו, כָּל שֶׁכֵּן אִם יָשׁוּב מִיִּרְאַת הַשֵּׁם וְאַהֲבָתוֹ, שֶׁנֶּאֱמַר (דברים ד, ל): "בַּצַּר לְךָ וּמְצָאוּךָ כֹּל הַדְּבָרִים הָאֵלֶּה בְּאַחֲרִית הַיָּמִים וְשַׁבְתָּ עַד ה' אֱלֹהֶיךָ וְשָׁמַעְתָּ בְּקוֹלוֹ". וְהִתְבָּאֵר בַּתּוֹרָה, כִּי יַעֲזֹר ה' לַשָּׁבִים כַּאֲשֶׁר אֵין יַד טִבְעָם מַשֶּׂגֶת וִיחַדֵּשׁ בְּקִרְבָּם רוּחַ טְהוֹרָה לְהַשִּׂיג מַעֲלַת אַהֲבָתוֹ, שֶׁנֶּאֱמַר (דברים ל, ב): "וְשַׁבְתָּ עַד ה' אֱלֹהֶיךָ וְשָׁמַעְתָּ בְקֹלוֹ כְּכֹל אֲשֶׁר אָנֹכִי מְצַוְּךָ הַיּוֹם אַתָּה וּבָנֶיךָ בְּכָל לְבָבְךָ וּבְכָל נַפְשֶׁךָ". וְאוֹמֵר בְּסוֹף הָעִנְיָן (דברים ל, ו): "וּמָל ה' אֱלֹהֶיךָ אֶת לְבָבְךָ וְאֶת לְבַב זַרְעֶךָ" – לְהַשִּׂיג אַהֲבָתוֹ. וְהַנְּבִיאִים וְהַכְּתוּבִים דִּבְּרוּ תָּמִיד עַל דְּבַר הַתְּשׁוּבָה, עַד כִּי בָּאוּ עִקְּרֵי הַתְּשׁוּבָה כֻּלָּם מְפֹרָשִׁים בְּדִבְרֵיהֶם כַּאֲשֶׁר יִתְבָּאֵר. וְדַע, כִּי הַחוֹטֵא כַּאֲשֶׁר יִתְאַחֵר לָשׁוּב מֵחַטָּאתוֹ יִכְבַּד עָלָיו מְאֹד עָנְשׁוֹ בְּכָל יוֹם, כִּי הוּא יוֹדֵעַ כִּי יָצָא הַקֶּצֶף עָלָיו וְיֵשׁ לוֹ מָנוֹס לָנוּס שָׁמָּה, וְהַמָּנוֹס הוּא הַתְּשׁוּבָה, וְהוּא עוֹמֵד בְּמִרְדּוֹ וְהִנּוֹ בְּרָעָתוֹ, וּבְיָדוֹ לָצֵאת מִתּוֹךְ הַהֲפֵכָה, וְלֹא יָגוּר מִפְּנֵי הָאַף וְהַחֵמָה, עַל כֵּן רָעָתוֹ רַבָּה. וְאָמְרוּ רַבּוֹתֵינוּ זִכְרוֹנָם לִבְרָכָה עַל הָעִנְיָן הַזֶּה (קהלת רבה ז, לב) מָשָׁל לְכַת שֶׁל לִסְטִים שֶׁחֲבָשָׁם הַמֶּלֶךְ בְּבֵית הָאֲסוּרִים, וְחָתְרוּ מַחְתֶּרֶת, פָּרְצוּ וַיַּעֲבֹרוּ וְנִשְׁאַר אֶחָד מֵהֶם. בָּא שַׂר בֵּית הַסֹּהַר וְרָאָה מַחְתֶּרֶת חֲתוּרָה וְהָאִישׁ הַהוּא עוֹדֶנּוּ עָצוּר, וַיַּךְ אוֹתוֹ בְּמַטֵּהוּ. אָמַר לוֹ: קְשֵׁה יוֹם! הֲלֹא הַמַּחְתֶּרֶת חֲתוּרָה לְפָנֶיךָ וְאֵיךְ לֹא מִהַרְתָּ הִמָּלֵט עַל נַפְשֶׁךָ?
In explanation of repentance and its principles Among the good things which God, may He be blessed, has bestowed upon His creations is the path which He prepared for them to ascend from the baseness of their actions, to escape the trap of their inequities, to hold their souls back from destruction and to remove His anger from upon them. Because of His goodness and uprightness, He has taught them and warned them to return to Him when they sin against Him - for He understands their nature, as it is stated (Psalms 25:8), "Good and upright is the Lord; therefore He shows sinners the way." [Even] if they greatly sin and rebel and act like treacherous betrayers - He does not close the doors of repentance to them, as it is stated (Isaiah 31:6), "Return, to Him to whom they have been so shamefully false." It is [also] stated (Jeremiah 3:22), "Turn back, O rebellious children, I will heal your afflictions." We are warned about repentance in several places in the Torah. It is explained that repentance is accepted even when the sinner repents because of his many troubles - how much more so [will it be accepted] if he returns because of fear or love of God - as it is stated (Deuteronomy 4:30), "When you are in distress because all these things have befallen you and, in the end, return to the Lord your God and obey Him." It is explained in the Torah that God will help those who repent beyond what their natural ability would allow; and that He renews a pure spirit within them, to reach great heights in His love - as it is stated (Deuteronomy 30:2), "And you return to the Lord your God, and you and your children heed His command with all your heart and soul, just as I enjoin upon you this day." Further, it is stated about the body of the matter (Deuteronomy 30:6), "Then the Lord, your God, will circumcise your heart and the hearts of your offspring," to acquire love for Him. And the Prophets and Writings constantly speak on the subject of repentance, such that the principles of repentance are all explained in their words, as will be explained. Know that the punishment for the sinner who delays repenting of his sin will grow much heavier for him every day. For he knows that [God's] wrath has gone forth against him and that he has an escape route from it - that escape being repentance - yet he still remains rebellious and stays within his evil. Even though it is within his power to leave from within the disorder, he does not fear the anger nor the rage. Thus, his evil is great (see also Midrash Kohelet [Kohelet Rabbah 7:15], which relates a parable illustrating this concept).