Teshuvah literally means "return" and is the word used to describe the concept of repentance in Judaism. Only by atoning for our sins can we restore balance to our relationship with God and with our fellow human beings.
Teshuvah is most frequently associated with the High Holy Days but people can seek forgiveness for wrongs they have committed at any time. There are several stages of teshuvah, including the sinner recognizing his or her wrongs, feeling sincere remorse and doing everything in their power to undo any damage that has been done. If a specific person has been wronged the offender must ask that person for forgiveness. The final stage of teshuvah is resolving to never commit such a sin again. According to Jewish tradition, by the third request the person who was wronged is required to grant forgiveness if the offender is sincerely remorseful and is taking steps to prevent similar wrongs from happening again.
Because teshuvah requires the sinner to ask forgiveness of the person they have offended it has been argued that a murderer cannot be forgiven for his or her crime. In order to do so they would have to ask the person they killed for forgiveness. There are two other offenses that come close to being unpardonable: defrauding the public and ruining a person's good name. In both cases it is nearly impossible to track down every person who was affected by the offense, for instance, every person affected by a monetary crime or every person who heard a rumor.