Two Types Of Teshuva

וְשַׁבְתָּ עַד ה' אֱלוֹקֶיךָ וְשָׁמַעְתָּ בְקֹלוֹ כְּכֹל אֲשֶׁר אָנֹכִי מְצַוְּךָ הַיּוֹם אַתָּה וּבָנֶיךָ בְּכָל לְבָבְךָ וּבְכָל נַפְשֶׁךָ ...  כִּי תִשְׁמַע בְּקוֹל ה' אֱלוֹקֶיךָ לִשְׁמֹר מִצְוֹתָיו וְחֻקֹּתָיו הַכְּתוּבָה בְּסֵפֶר הַתּוֹרָה הַזֶּה כִּי תָשׁוּב אֶל ה' אֱלוֹקֶיךָ בְּכָל לְבָבְךָ וּבְכָל נַפְשֶׁךָ.  In Ch. 30 possuk 2 and 10 the Torah repeats the teshuva of Klal Yisroel.  Why is it repeated, what are the multiple stages?  Why in the first possuk does it first say וְשַׁבְתָּ and subsequently וְשָׁמַעְתָּ but in the second possuk תִשְׁמַע precedes תָשׁוּב?  And why does the first possuk say 'וְשַׁבְתָּ עַד ה but the seond time it says 'אֶל ה?  The Chasam Sofer has an approach regarding the repetition, see here.  Others say that these are two levels of teshuva.  The first possuk follows after the one has experienced the berachot and klalot (as it says in the previous possuk.)  Then one turns to Hashem from yirah. That is teshuva miyirah, teshuva from fear, where the sin is mitigated.  The second level is coming after it says ומל ה אלקיך לאהבה את יי, one does teshuva from love of Hashem where the sin is turned into a merit.  That is why the first time it says 'עד ה, the person reaches to Hashem but there is still something separating between them.  The second time it is 'אל ה, one comes totally to Hashem as in בא אל הבית, one enters inside (see Ktav V'kabbalah.)  That also may explain if the שמעת  or the תשוב comes first.  In the first possuk, one is doing teshuva from fear, one turns toward Hashem as a consequence of the events in the world around them and then one focuses on the שמעת, on the philosophy.  In the second possuk it is the 'דבר ה, the greatness of the 'דבר ה that inspires one to come to do teshuva from אהבה.  

The Tzlach (Berachot 4b) says a similar idea in the haftorah for Shabbas teshuva,    שׁ֚וּבָה יִשְׂרָאֵ֔ל עַ֖ד י״י֣ אלקיך כי כשלת בעונך קְח֤וּ עִמָּכֶם֙ דְּבָרִ֔ים וְשׁ֖וּבוּ אֶל־י״י֑ כׇּל־תִּשָּׂ֤א עָוֺן֙ וְקַח־ט֔וֹב.  Again we can ask why the repetition of teshuva and the switch from עד to אל?  He says the first time it is teshuva from fear, the sin still remains, it is still called an עון.  The second time is teshuva from love, then the sin is turned into טוב.  

The Maharsha on Yoma (86b) asks how is it that זְּדוֹנוֹת נַעֲשׂוֹת לוֹ כִּזְכִיּוֹת if one does teshuva from love הוא לכאורה דבר תמוה דנמצא חוטא נשכר?  The Tanya explains the idea is that everything has holy sparks in it.  Things that are forbidden the sparks are אסורת tied up and can not be accessed.  However, through teshuva one is able to release these sparks from their bondage and the merits are the holy sparks that were in the averah itself.  Its not that the averah turns into a mitzvah but by releasing the bondages of issur the averah turns naturally into a mitzvah.