Judaism sees the world as a web of relationships: our relationship with God, our many relationships with other people. It is the nature of relationships to ebb and flow. There are good times and bad times. There are times of intimacy and closeness and there are times of alienation and distance. This is true for our relationships with other people and it is the case for our relationship with God. At the root of rectify any relationship which has gone awry is the need for sincere teshuvah (repentance) and in some cases kapparah (atonement). The hurt must be healed and the mistakes repaired and resolved in order for the relationship to resume in a healthy manner. Repentance, then, is the key to realigning relationships that are off-track.
Jewish tradition does pretend or expect that humans are perfect or will ever be perfect. There is no pretense that we are capable of avoiding sin altogether and are therefore miserable failures because we are not perfect. The focus is rather twofold: (1) correcting mistakes we have made; and (2) changing ourselves so as to avoid making the same mistakes again in our lives.
Given the centrality of repentance in keeping relationships healthy, it is not surprising that prayers for forgiveness figure prominently into the daily liturgy. Each morning, afternoon, and afternoon, one is to recite the Amidah, a series of benedictions which, on weekdays, include petitions to God. Prayers for repentance, forgiveness, and the redemption that result for a reconciled relationship top the list. While we direct our prayers to God, the theme of the prayers reminds us to examine our relationships with other human beings at regular intervals, as well.
In addition, ten days are set aside each autumn for the People Israel -- Jews throughout the world -- to engage in repentance and atonement. Repentance is consider so important for setting relationships aright and living our lives better that it is considered appropriate and fitting for the community to stop everything it is doing to gather for prayer on Rosh Hashanah and ask God for forgiveness for our sins, and to continue those prayers for 10 days, culminating in Yom Kippur, the Day of Atonement. Perhaps there is a very human reason at work, as well: It is much more likely that we will all succeed at the work of repentance if everyone else is engaged in the same task at the same time.
The Mishnah makes clear, however, that rote recital of prayers for repentance without any sincere repentance of the heart, is meaningless:
One who says: I will sin and repent, then I will sin again and repent again, is not really repentance. And one who says: I will sin, and the Day of Atonement will atone for me, will find that the day will not avail for atonement.
For transgressions against God, the Day of Atonement atones; but for transgressions of one human being against another, the Day of Atonement does not atone until they have made peace with one another.
The passage above illustrates an interesting difference between Judaism and some other religious traditions. For Jews, every sin against another human being is also a sin against God, who promulgates laws of kindness, honesty, and decency. If I have hurt you, I have hurt God, as well. However, I cannot come first to God to seek forgiveness. I must first approach the person whom I have wronged and ask for forgiveness. Indeed, I must ask for forgiveness -- sincerely -- on three occasions, if necessary. Only once I have reconciled with the one whom I have wronged (or made three honest attempts at reconciliation) may I approach God and seek forgiveness. In other words, God doesn't want to talk to me about the sin until I have made every effort to correct my relationship with the person I have wronged.
The Rabbis emphasized that God is desirous of our repentance and inclined to forgive. In the midrash on Shir Ha Shirim (the Song of Songs) they wrote:
"Open to Me [Song of Songs 5:2]". Make for Me an opening (of repentance), an opening as narrow as the point of a needle, and I will make the opening so wide (for pardon) that camps full of soldiers and siege engines could enter it.
Similarly, they taught that while the gates to prayer (that is, God's willingness to hear prayer) are sometimes open and sometimes closed, the gates of repentance are always open:
R. Helbo asked R. Samuel bar Nahman: since I have heard of you as a master of Aggadah, tell me what is meant by the verse Thou has covered thyself with a cloud so that no prayer can pass through [Lamentations 3:44]? R. Samuel answered: Prayer is likened to an immersion pool, but repentance is likened to the sea. Just as an immersion pool is at times open and at other times locked, so the gates of prayer are at times open and at other times locked. But the sea is always open, even as the gates of repentance are always open. [Lamentations Rabbah 3:43, section 9].
Rabbi Hama, the son of Hanina is quoted in the Babylonian Talmud as teaching: "Great is repentance, for it brings healing to the world, as it is said: I will heal their affliction, generously will I take them back in love [Hosea 14:5]." Rabbi Jonathan opined: "Great is repentance for it brings redemption, as it is said: A redeemer will come to Zion, and to them that turn from transgression in Jacob [Isaiah 59:20]." [tractate Yoma 86a]
For the Sages, we are what we do and say, and hence our deeds and words -- which have the power to heal or destroy -- are enormously important. "Days are scrolls," wrote Bachya ibn Pakuda in the 11th century, "Write on them only what you want remembered." What we would not have remembered, we can "erase" through teshuvah (repentance) and atonement.
The true test of repentance is whether a person, placed in the same situation in which s/he once found himself and which occasioned the original sin, and with the opportunity to commit the sin again, does. If s/he commits the same sin again, the repentance was never sincere. If s/he refrains from committing the sin again, then s/he was sincere.
In addition to repentance, Judaism requires atonement. Atonement is the effort to "pay back" for the sin committed. If I stole property, for example, I must make restitution. If I spread a vile rumor that hurt someone's reputation, I must do everything possible to help that person restore the reputation they lost on my account. In addition, atonement sometimes takes the form of punishment for the sin committed. On Yom Kippur, all adult Jews engage in a full 25-hour fast, from sundown on the eve of Yom Kippur until three stars appear in the sky at the end of Yom Kippur, as atonement for sins for which they have repented. The fast is meant as a form of self-denial and self-affliction; it is not so severe as to endanger a healthy adult, but it is unpleasant and inconvenient, and serves to make one who truly prayers and repents to feel that s/he has "paid the price." Such a payment permits one to spiritually wipe clean the slate and begin anew. We know guilt has a positive function: it is a message from our consciences to alert us to wrongdoing; however excessive guilt is destructive and paralyzing. The fast of Yom Kippur is intended to prevent excessive guilt from holding us back from becoming better human beings and better Jews.