Repentance

There is a positive Biblical commandment to repent and admit one's sins (Vidduy).

General

1. Even though there is important and effective to perform repentance all year round, during the Aseret Yemei Teshuva there is an additional aspect of having one's Teshuva accepted by Hashem immediately.

Procedure

1. If a person sinned, whether it be a positive command or a negative command - whether willingly or inadvertently - when he repents, and returns from his sin, he must confess before Hashem, as it states (במדבר ה:ו-ז) : "If a man or a woman commit any of the sins of man... they must confess the sin that they committed." This refers to a verbal confession. This confession is a positive command.
2. How does one confess: He states: "I implore You, God, I sinned, I transgressed, I committed sins before You by doing the following. Behold, I regret and am embarrassed for my deeds. I promise never to repeat this act again."
3. The essential parts of תשובה are admitting the sin, regretting it, and promising never to do it again. Whoever elaborates upon these matters and performs a more serious teshuva is praiseworthy.
4. Almost every כפרה is contingent upon doing תשובה. For example, קרבנות only affect atonement if you do תשובה. Similarly, Yom Kippur only atones for those who repent.

Effects of Teshuva

1. At present, since we don't have the בית המקדש or the מזבח, the only way we can receive atonement is by doing תשובה .תשובה atones for all sins.
2. Even though תשובה atones for all sins and the essence of Yom Kippur brings atonement, sometimes you receive atonement immediately and sometimes it is only after a long time. If a person violates a positive commandment which is not punishable by כרת and does תשובה, he is forgiven immediately. By contrast, if a person violates a negative commandment that is not punishable by כרת or מיתת בית דין and repents, תשובה has a partial effect and Yom Kippur atones completely.
3. If a person violates sins punishable by כרת or מיתת בית דין and does תשובה ,תשובה and Yom Kippur have an incomplete effect; atonement is complete when sufferings come upon him.
4. Someone who creates a 'חילול ה, Teshuvah, Yom Kippur and suffering provide partial atonement which is only complete with death.

Greatness of Teshuva

1. It is so great that even someone who was wicked, despicable and distanced from Hashem one day, can become beloved, precious and close to Hashem the next day through תשובה.