Views on Vidduy

One of the parts of teshuva and in fact according to  the Minchas Chiunch's understanding of the Rambam, the entirety of the mitzvah of teshuva, is vidduy.  Why is it s important for one to mention their sins explicitly?  

I would like to share three interpretations.   

In it's most basic level, vidduy allows one to come to fully acknowledge their sins.  When one does a mental process of teshuva, their is still wiggle room in the back of one's mind to think that they are really not guilty but by having to pronounce it, one must truly acknowledge their sins (Rav Soloveitchik.)  

Rav Hutner (Pachad Yitzchak mammer 18) cites the Gemarah (Yoma 86b) says one who repeats vidduy for a sin that was not committed through the year on Y.K .is עליו הכתוב אומר (משלי כו, יא) ככלב שב על קיאו כסיל שונה באולתו.  We see from this Gemarah that vidduy is referred to as קיאו, as vomit.  Why is vidduy called an act of vomit?  Rav Hutner explains that the original sin of mankind which the עץ הדעת brought רע from outside a person into the person.  Before the sin, temptation came to mankind from the outside.  It is only after the sin that now man's temptations come from within the individual.  When one does vidduy they are taking the רע that has built up within a person and bringing it out.  One is spitting the temptations, the trauma, that has built up inside and pushing it out.  That is why vidduy is called vomiting.  One has to throw up all the poison digested throughout the year.  In other words, when one does vidduy and acknowledges one's sins, one separates themselves from their sins and is able to view them as an outsider.  

A similar idea can be found in the Meshech Chochma on the possuk (Bamidbar 6:13) וְזֹ֥את תּוֹרַ֖ת הַנָּזִ֑יר בְּי֗וֹם מְלֹאת֙ יְמֵ֣י נִזְר֔וֹ יָבִ֣יא אֹת֔וֹ אֶל־פֶּ֖תַח אֹ֥הֶל מוֹעֵֽד.  What does it mean יביא אותו?  That the nazir has reached a point where he views his guf, his bodily pleasures as אותו, as someone else, an outsider (see also Sforno there.)

The possuk in Shmuel (2:12:13) says  וַיֹּ֤אמֶר דָּוִד֙ אֶל⁠־נָתָ֔ן חָטָ֖אתִי לַי״י֑  וַיֹּ֨אמֶר נָתָ֜ן אֶל⁠־דָּוִ֗ד גַּם⁠־י״י֛ הֶעֱבִ֥יר חַטָּאתְךָ֖ לֹ֥א תָמֽוּת.  Why is there a break in the middle of the possuk?  The Gra explains the Dovid was about to say the entire nussach of the vidduy חטאתי עויתי פשעתי but the navi stopped him after חטאתי and said your sin is already forgiven.  There are different ways the Gra is purported to have explained the idea and one of the ways (in Barak Hashachar in likkutim) is that vidduy works to kill the קטיגור created via a sin but Dovid did such a level of teshuva that merely by saying חטאתי he killed the קטיגור monster.  The Or Hachaim (Acharei 16:7) also says this idea that a monster is created via a sin and he say that is what the navi was telling Dovid לא תמות, meaning you have slayed the monster and it won't attack you.  ולזה כמשמחל ה׳ לדוד הודיעו שאבד הכח הרע שנולד מהמעשה הבלתי הגון כאומרו (שמואל ב יב) גם ה׳ העביר חטאתך לא תמות, הכוונה בזה כיון שהחטא שעושה האדם נברא ממנו הנפרע מעושהו ממילא באבוד המשחית אין משחית, וזה שאמר לו ה׳ שאחר שהעביר חטאתו לא ימות כי אין ממית.  With this idea, the Or Hachaim says that is the point of סמיכה on a korban.  When one does סמיכה it attaches the korban to the evil monster created via the sin and then the adovah of the korban kills the monster.  The Tzemach Tzedek (Derech Mitzvosecha) also says that teshuva itself cleanses the sin but there is still left the קטיגור created via one's sins and that is killed by saying vidduy.  Rav Yeruchem Olshin (Yarech L'moadim siman 55) asks why does one need to kill the monster, isn't it enough with teshuva, at least teshuva out of love which totally erases the averah?  Why would there be a monster left if the averah is erased?  He wants to say that even though teshuva erases the sin that is only in terms of going forward, however the action of the sin in the past still happened (נעקר למפרע מכאן ולהבא, עיי"ש.)  

I think all these interpretations go hand in hand.  It is by fully coming to terms with one's sin and acknowledging them  that one is able to separate themselves from the sin.  Only after a true self- evaluation can one judge the sin as an outsider and say they don't want to be a part of that anymore. That regurgitation of sin, that cleaning of self by throwing the effects of sin out, remove the קטיגור from within one's self and then the קטיגור outside created via the sin has no hold over a person anymore either.