The Rambam (Hilchos Teshuvah 1:1) writes, "If a person committed an aveirah, he must say viduy before Hashem, as it states את והתודו עשו אשר חטאתם, 'They should confess their sins.' This is a mitzvas asei."
A mitzvah must be performed with joy; therefore, viduy should also be said with joy. This could be the reason we say אשמנו and אל חטא on Yom Kippur with a tune. In addition to the joy of the mitzvah, we are also happy because we know that with this viduy, we are coming closer to Hashem.
Once, after the viduy of Yom Kippur, the chazan of Zaslav said, "Ribono Shel Olam, if the Jewish nation hadn't sinned, where would you hear such a sweet Ashamnu?" Rebbe Zusha of Anipoli zt'l would say, "If the Jewish nation hadn't sinned, where would Hakadosh Baruch Hu get a ונסלח such as the Jewish nation says on Yom Kippur night, with such a tune and outpouring of the soul?"
Rebbe Yaakov Yechezkiyahu of Pupa zt'l taught that when one is about to say viduy he should imagine crossing a forest alone and being assaulted by a band of thieves. They are sharpening their knives, and he knows his end is near. He asks the thieves to allow him a last wish, and they permit it. His last wish is to say viduy. Imagine this scenario, and then say the viduy of Yom Kippur.
The Yismach Yisrael zt'l said that when he was young, he heard from magidim that when one says viduy he should think: There will yet be another time when I will say viduy. That will be after my demise when I stand before the beis din in heaven. I will be dressed in a tallis and kittel, I will say viduy like I'm saying it now, but then it won't help me. Now I can still fix everything with my viduy."
Immediate Atonement
When you ask for forgiveness, Hashem forgives you right away. You don't have to wait a week or a month, and you don't need yesurim, and you also don't need many tefillos. You ask Hashem for forgiveness, and He forgives. It is as simple as that.
The Baal HaTanya (Igeres HaTeshuvah 11) proves this from the brachah לנו סלח in Shemonah Esrei. Immediately after we request Hashem to forgive us, we thank Hashem for doing so, as we say, לסלוח המרבה חנון 'ה אתה ברוך. The Baal HaTanya writes, "Every day in Shemonah Esrei, we ask Hashem to forgive us, as we say, לנו סלח. After that, we immediately say, לסלוח המרבה חנון 'ה אתה ברוך. But behold, when one is in doubt about a brachah, he mustn't make a brachah lest his brachah be in vain. How can we bless Hashem for forgiving us? Perhaps Hashem didn't accept our teshuvah and didn't forgive us? The answer is: We have no doubt. After one says לנו מחל לנו סלח, he is forgiven. And if we hadn't sinned again, we would immediately be redeemed, as the next brachah states, ברוך ישראל גואל 'ה אתה ."
The Noam Elimelech zy'a writes, "The Torah teaches us to say viduy with confidence in Hashem's compassion and belief that Hashem will forgive our sins. One shouldn't say viduy with sadness and yeush, as this brings on dinim; rather say viduy with bitachon. Trust that He will forgive you. As it states (Mishlei 28:13), ירוחם ועוזב ומודה, 'He who confesses and abandons [sin] will obtain mercy.'"
Bilaam also said viduy. When he saw the malach standing before him, he said חטאתי, "I sinned," and the Midrash writes, "Bilaam was a clever rasha. He knew that his only protection from punishment was teshuvah. When he said חטאתי he was protected."
The Beis Yisrael zt'l said it's a mitzvah to publicize this Midrash, particularly to bachurim (who often feel that Hashem won't forgive them). Even the rasha Bilaam attained forgiveness when he said viduy (although his teshuvah wasn't sincere).
Viduy is written in alphabetical order: זלנו'ג גדנו'ב שמנו'א and so on. The Reishis Chachmah explains that our aveiros tainted all the letters of the alef beis, which are the letters of Creation, and we correct them with the viduy.
However, notes the Reishis Chachmah, the first word of the viduy is חטאנו, as we say ...אשמנו חטאנו ואבותינו אנחנו אבל. Why don't we begin with אשמנו?
The Reishis Chachmah answers that it is important to begin viduy with חטאתי because this word removes the mekatreg (the Satan who proclaims our sins). If we were to start by telling our aveiros, the Satan could go up to heaven and say, "Listen to what he's saying. He himself agrees that he sinned." But after we said חטאנו, the Satan is silenced. He can't speak out against us. So now we can say viduy in the order of the alef beis.
In the era of the Beis HaMikdash there was a mitzvah called viduy maasros, to go to the beis hamikdash twice in seven years to proclaim that we observed all the halachos of maasar, terumah, and the like. Surprisingly, this mitzvah is called viduy since we announce that we kept the halachos, not confessing that we have sinned.
For example, by viduy maasros one says, שכחתי ולא ממצותיך עברתי לא, "I didn't transgress your mitzvos, and I didn't forget" (Devarim 26:13). Why are these words called viduy (confessions)?
Rebbe Shalom Chaim of Koidenov zt'l answers that both Hashem and the person, are speaking in these pesukim: The person says, ממצותיך עברתי, "I transgressed your mitzvos," and Hashem replies, עברתי לא "you didn't transgress." The person says, שכחתי, "I forgot to keep the mitzvos," and Hashem responds, שכחתי לא, "you didn't forget."
And this is because the viduy wipes away sins entirely. This explains why it's called viduy maasros, a confession. Man confesses his errors, and Hashem responds that there is no longer any sin. Similarly, when we say חטאתי, Hashem replies, "You didn't sin," and the sin is totally removed.
Reb Chaim Volozhiner zt'l traveled to his son's chasunah and stopped in the middle of the way to daven shacharis. It was a day that the Torah was read, but the beis medresh he was in didn't have a sefer Torah. Reb Chaim questioned the Rav about that, and he replied, "The closest sefer Torah is far from here. We aren't obligated to go there to hear the reading of the Torah."
Reb Chaim Volozhiner disagreed but remained silent. He didn't want to debate the issue with the Rav before the congregation. When Reb Chaim returned home after the chasunah, he heard that his personal sefer Torah was stolen. He understood that he was being punished for not demanding that the Torah be read that morning.
While he said viduy for this transgression, the police arrived with the stolen sefer Torah. They had found the thief.
On Yom Kippur, we say viduy with אשמנו and we say viduy with the חטא עלs. But, surprisingly, we don’t say an חטא על for bitul Torah. Bitul Torah is from the severest aveiros; we would assume that it deserves its own על חטא.
The Sfas Emes zt'l answers that we say, דעת בבלי לפניך שחטאנו חטא על, "For the sin that we committed before You without knowledge." This refers to when one committed aveiros because he didn't know that the Torah forbade his deeds. So, ultimately, this is viduy for not learning Torah. If he had known Torah, he wouldn’t have committed those aveiros.
Furthermore, we say, לפניך שחטאנו חטא על עול בפריקת, "For the sin that we committed before you by throwing off the yoke [of Heaven]." The Sfas Emes writes that when one doesn't study Torah, this can be called casting off the yoke of Heaven.
Rebbe Bunim of Peshischa zt'l told the following parable:
There was a home that was very dirty. The homeowner tried to clean it many times but was never successful. He finally came up with a plan that would help solve his problem. He invited the king to visit him at his home. The king won't enter a dirty house, so the king's servants came before the visit to clean up and prepare the house for the royal visit. The man gained doubly: He hosted the king, and his home got clean.
We say in the zemiros of Motzei Shabbos, חטאי על, for my sins, תעבור עבור, come visit me. We earn doubly: Hashem comes to us, and our sins are removed.
This occurs on Yom Kippur. Hashem comes to us; therefore, we are cleansed from all our aveiros. This seems to be the intention of the Mishnah (end of Yoma), אשריכם עקיבא 'ר אמר שבשמים אביכם אתכם מטהר ומי מטהרים אתם מי לפני ישראל , "Yisrael, you are fortunate! Before Whom do you purify yourselves? Before your Father in heaven!"
On Yom Kippur, we stand before Hashem, and that is the root of our atonement.
