I
The scapegoat atones for all sins if one repents. Otherwise, it atones only for lesser sins. Grave sins, punishable by kares or misas beis din, as well as false or vain oaths, are not atoned. (Rambam Teshuva 1:2)
Two questions arise. First, atonement without repentance, achieved vicariously via a scapegoat, seems impossible. After all, an offering of a wicked person is abominable (Mishlei 21:27). Second, why the distinction between lesser and grave sins?
Rav Soloveitchik zt"l answered both questions based on the Rambam's introductory phrase: "The scapegoat… is an atonement for all Israel." A wicked, unrepentant person has no individual atonement. However, he partakes of the communal atonement granted to Am Yisrael as such. Grave sins remove the person from the nation and preclude participation in the national atonement. Kares cuts the soul off from its people (Bamidbar 19:13).
The Rav zt"l cited the bracha recited on Yom Kippur: The King who pardons and forgives our sins and the sins (avonos) of His people Israel. Hashem forgives individuals, and the nation as a whole. He also removes our guilt (ashma), a term associated with desolation (shmama, Ramban Vayikra 5:19). Since Klal Yisrael will never be destroyed, the term guilt (ashma) is limited to individuals (On Repentance, 1996 ed., p. 97-109).
Presumably, removal from the nation by capital punishment resembles kares. And one who swears falsely or in vain is distanced by everyone, because others are punishable when one close to them swears falsely, more so than for other sins (Shevuos 39a,b). As such communal atonement is not possible for these sins.
Yom Kippur itself achieves atonement even in the absence of complete teshuva [see Atonement on Yom Kippur]. We can postulate that this, too, is a national atonement, as the bracha implies.
According to Rebbe (Yoma 85b), Yom Kippur atones for (nearly) all sins without teshuva. Why, then, was the Bais Hamikdash destroyed? [See Tosfos Yeshanim, who ask this question and suggest that the atonement is only partial.]
A nation is judged based on the majority of its people (Rambam Teshuva 3:1). Therefore, as the sins of Am Yisrael increased, the scapegoat no longer achieved full national atonement symbolized by red thread turning white (Yoma 39a, 67a). Similarly, Yom Kippur lost its effectiveness according to Rebbe. As a communal atonement, Yom Kippur requires a majority of individuals who repent and deserve atonement. Only then can the unworthy be included.
II
Yom Kippur does not atone for interpersonal sins until one appeases [yeratzeh] the wronged person. (Yoma 85b)
Even if the appeasement is continually rebuffed, Yom Kippur atones. It does not state until the wronged person is appeased [yisratzeh] (Pri Chadash O.C. 606:1).
Conversely, if one grants forgiveness without being asked, it is not fully effective. For this reason, Rav appeared before the butcher who had wronged him, hoping that the butcher would appease him (Yoma 87a). Rav did not merely forgive him from afar.
Nonetheless, forgiving from afar is partially effective. This is evidenced by our forgiving all those who wronged us in Tefila Zakka on Yom Kippur eve. We pray that no one should be punished on our account, a phrase many say nightly. Forgiving others nightly results in longevity (Megilla 28a, M.B. 239:9).
Apparently, forgiving sins is comparable to forgiving money. It removes punishment on account of the one who was wronged and forgives. But it does not entitle the sinner to the atonement of Yom Kippur.
This can be explained based on our earlier analysis. One cannot enjoy communal atonement when removed from the community. Interpersonal sins remove the sinner from the wronged person and, by extension, from the community. If he appeases his fellow and asks repeatedly for forgiveness, he has done all that he can to make amends. As such, he reenters the community and benefits from Yom Kippur's communal atonement.
By contrast, the wronged person who does not grant forgiveness after three requests is the sinner. For this reason one should not ask forgiveness more than three times (Rambam Teshuva 2:9). It is now assumed (chazaka) that the wronged person will not grant forgiveness. Asking him again would only make him a bigger sinner and, as such, is not allowed.
III
It is customary to ask forgiveness on Erev Yom Kippur, as the midrash teaches: Hashem ordained ten days of teshuva, during which even if one person repents, his teshuva is accepted like the teshuva of the community. Therefore, all Israel should repent and make peace between a man and his fellow, and forgive one another on Erev Yom Kippur so that their repentance and prayer should be received by Hashem with peace and with love. (Mordechai, Yoma 723)
This citation proves the aforementioned thesis. Yom Kippur is special because an individual's repentance is treated like that of a community. If one asks forgiveness of his fellow, he is included in the community, since he seeks closeness with everyone, even someone whom he has wronged and had been distanced from him.
The midrash adds two points. It includes all the ten days of teshuva, and mentions prayer as well. This is based on the Gemara (Rosh Hashana 18a):
Hashem is close to us whenever we call Him (Devarim 4:7). Yet it states (Yeshaya 55:6): Call Hashem when He is close, i.e., in Aseres Yemei Teshuva. The former refers to the community, the latter to an individual.
The midrash interprets that even in Aseres Yemei Teshuva, we require the merit of the tzibbur, but the teshuva of an individual is treated like that of a community. This is achieved only by asking forgiveness of one's fellow, which reintegrates the petitioner into the community and its atonement.
"To whom does Hashem grant atonement? To one who forgives others who wrong him" (Rosh Hashana 17a). One who overcomes his natural inclination to respond in kind to a person who pained him, but rather forgives the wrongdoer, belongs more strongly to the community. As such, he is granted the all-important communal atonement.
The angels asked, "Why does Yisrael not say Hallel on Rosh Hashana and Yom Kippur?" Hashem said, "The King judges, the books of life and death are open, and Israel should say Hallel?" (Arachin 10b)
The angels' very question is perplexing. It must be based on the statement, "There was no greater holiday for Yisrael that Yom Kippur" (Taanis 26b), "a day of atonement" (30b). Am Yisrael is guaranteed atonement. This warrants Hallel, as the angels asked. Hashem responds that no individual is guaranteed to be part of the communal atonement. The individual fears judgment and death and cannot recite Hallel (Rabbi C.Y. Goldvicht z"l).
As we approach Yom Kippur, we should do all that we can to become more strongly connected to the tzibbur. We should both ask and grant forgiveness. We should do more to help other individuals and the community at large.
On Yom Kippur itself, we must include even sinners in our fast (Krisus 6b) and prayers (introduction to Kol Nidrei). It is a day to institute love and friendship and to forsake jealousy and competition (Mussaf).
May each and every one of us merit both the individual and communal atonement of Yom Kippur. May Am Yisrael forsake the baseless hatred which caused the Churban and merit the rebuilding of the Beis Hamikdash and the restoration of the powerful communal atonement of the Yom Kippur service.