I saw this question on one of the blogs I follow. I'd like to share it here and then follow it with my suggested answer:
Here is a question I heard from Rav Mordechai Elon, in the name of the Hi”da, about the nature of Teshuva. Fasten your seat belts because it is quite a difficult question. Hopefully, some of you will have some good answers. I plan on posting my own answer during Chol Hamoed Sukkot. The answer I have bring an incredible understanding to our holidays and to the concept of Teshuva. Still, enjoy this post - the question is as sweet as the answer, and I can’t wait to read your answers as well.
There is a concept in Halacha called “Lav Hanitek Leasseh”. This concept, a very technical legal concept, is defined as follows: If there is a Lav, a negative commandment, which is then connected to an asseh, a positive commandment, then it is a Lav Hanitek LeAsseh. For example, if you steal (going against a negative commandment), you then need to give back what you have stolen (a positive commandment related to this negative commandment). Therefore, the commandment not to steal is a Lav Hanitek LeAsseh.
On the other hand, if you have a negative commandment which is NOT related to a positive commandment , it is NOT called a Lav Hanitek LeAsseh. Any negative commandment which is not followed by a positive commandment related to it DOES NOT fall in this category.
This differentiation has a practical difference (Nafka Minah) in Jewish Law - We get Malkout (flagellation) for going against any negative commandment except for a Lav Hanitek LeAsseh . (There are other exception to this rule but they are not relevant to this question: A Lav She-ein Bo Maaseh and a Lav Sheyesh Bo Mitat Beit Din.) Again: if it is a regular negative commadment, you get Malkout for going against it. If it is a Lav Hanitek LeAsseh, you don’t.
Now comes the most incredible part of the question. There is a Mahloket between the Rambam and the Ramban. The Rambam holds that Teshuvah is not a mitzvah from the torah. If you sin, you sin, and then you need to do teshuva but its not a Mitzvah from the torah to do Teshuvah. We won’t deal with his opinion right now.
On the other hand, the Ramban says that Teshuvah is a Mitzvah Min Hatorah, a positive commandment from the torah.
Now, lets formulate this Ramban in the way it is usually understood: If someone sins, then he has the positive obligation of doing teshuva. How does this apply to a negative commandment? If someone goes against a negative commandment, then he has the obligation to do teshuva. This applies to ANY negative commandment!
Rav Elon quotes the Hidah which asks an absolutely incredible question. The Hi”dah asks: If the opinion of the Ramban is right, then all the negative commandments in the torah are Lav Hanitek LeAsseh! Think about it: If someone goes against any negative commandment, then he has the obligation to do teshuva. This is the very definition of a Lav Hanitek LeAsseh! But we have a problem! If this is the case, then, the punishment of Malkout (flagellation) can NEVER apply, since it only applies on negative commandments which are NOT Lav Hanitek LeAsseh! However, Malkout is a form of punishment from the Torah! How can it be possible that it would never apply? How can it be possible that we can’t even think, conceptually, of a time when this punishment can apply? This is impossible!
We all know the Ramban did not make stupid mistakes so the Hidah asks: What did the Ramban mean when he said Teshuva was a Mitzvat Asseh? We cannot just understand it through its simple literal meaning because, as we have seen, it would make absolutely no sense and would not be coherent with the rest of Torah!
Okay, so here goes:
First of all, according to many authorities, the Rambam does hold that teshuva is a mitzva d'oraisa but at Dan notes, that's a subject that's best left for its own discussion.
However, I believe the answer to this question is due to the special relationship of teshuvah to the mitzvah it's atoning for.
Consider the case he notes as problematic: the lav hanitek l'aseh. Now, if one looks at the relationship between the lav and the aseh, a clear connection develops. The aseh only becomes incumbent on the person after the transgression occurs. Further, it is directly related to rectifying the misdeed caused by the transgression. Having done A, I must do a specific B in order to avoid a whippin'.
Teshuvah is different. As opposed to B rectifying misdeed A, teshuvah rather recitifies the fact that a misdeed was done in the first place. In other words, in the case of lav hanitek l'aseh I can fix the problem by a corrective action. Teshuvah does not fix anything like that. Rather it acts on the taint left on my soul by the misdeed and inclination that led me to commit it in the first place.
For this reason, teshuvah would still be relevant and a necessary obligation even if sone did a lav hanitek l'aseh.
Any other answers out there?