Obtaining Tahara

Rabbenu Yona holds that there is an additional mitzvah of teshuva on Yom Kippur besides the mitzvah all year round.  What is the nature of this mitzvah?  

The Rambam in the beginning of the Laws of Teshuva says one must say viduy for sins done wantonly or by accident, he does not include אונס.  Furthermore, the Aruch Hashulchan (602:7) points out that the Rambam in Perush HaMishna end of Yoma indicates that there is no viduy for ones.   Why is there no viduy for ones?  Because an action done in ones is not considered to be the fault of the participant at all (as opposed to an accident which comes about due to some form of negligence.)  However, we say on Yom Kippur על חטא שחטאנו לפניך באונס.  This would indicate that one has to say viduy even for actions committed באונס?

The Rambam in Teshuva (2:8) says that averot that one said viduy for on a previous Yom Kippur, one says viduy for them on the following Yom Kippur's as well.  The Rambam does not say this regarding the viduy said throughout the year for a sin in Chapter 1, this is a specific din for Yom Kippur.  What is the nature of this din?

What we see is that even though teshuva and viduy exist all year long, the viduy of Yom Kippur is distinct from that of the rest of the year.  As Rav Soloveitchik points out (Harraray Kedem,) the first chapter of the Laws of Teshuva in the Rambam deals with teshuva and viduy throughout the year.  The second chapter deals with laws specific to the teshuva and viduy process of Yom Kippur.  The process done on Yom Kippur is to accomplish more than teshuva for sins but to attain tahara, לפני ה תטהרו.  This tahara process involves one to be cleansed and removed from any sort of sin brought into the world due to one's actions.  Hence we say viduy on sins done even באונס.  That is why it is put right next to wanton sins, על חטא שחטאנו לפניך באונס וברצון, meaning one is being cleaned from all specks of sin from the worst of sins all the way down to a sin having brought about even באונס.  

This is the reason why one says viduy even for sins already confessed previously.  That is not necessary as part of the strict teshuva process but for taharah one must absolve himself of all previous connection to sin.   

This is what Rabbenu Yona is telling us is the additional mitzvah on Yom Kippur.  This is a mitzvah beyond the bounds of teshuva, it is a mitzvah of taharah. 

What does this level of taharah mean?  Yom Kippur is the culmination of a 40 day process started at the beginning of Elul of returning to Hashem.  The Maharal in Gur Aryeh (Shoftim) says that a person gets 39 lashes for violating a lav for it takes 40 days for an embryo to form.  The first day is the pure essence of the person and then there are 39 days to create the makeup of the individual. It is the additional 39 levels of a person that can become contaminated by sin but not the pure essence of the 40th.  On Yom Kippur we are unraveled all the way back to the innermost essence of a person which desires to be attached to Hashem.  The viduy of Yom Kippur is the outward expression of the complete eradication of any connection to sin which becomes attached to the externality of the person and we proclaim our innermost desire to become attached to Hashem.   

(Based upon the sefer L'teshuvas Hashana, Yarech L'moadim siman 43, and article of Rabbi Rosensweig.)