הלכות תשובה א,ב-ג

(2) The Azazel-goat, because it is atoning for all Israel, the High-Priest confesses over it in the speech of all Israel, even as it is said: "And confess over him all the iniquities of the children of Israel" (Lev. 16.21). The Azazel-goat, moreover, atones for all transgressions mentioned in the Torah, both, minor and major, whether one committed it in spite or whether he committed it in error, whether it was done by him knowingly or unknowingly— for all the Azazel-goat atones, provided the sinner did repent. But if he repenteth not, the Azazel-goat atones not save for his minor sins. And, what are the minor and what are the major sins? The major sins are such as carry the guilt of death or excision, included among which are also vain and false swearing, although they do not carry the guilt of excision; and all other prohibitive or mandatory commandments which do not carry the guilt of excision are the minor.

At this time, when the Temple is not established and, therefore, no altar to atone for us, there is nothing else left for us but repentance. Repentance atones for all sins. Even one who was an evildoer all his life but repented in the end, not a thing of the wickedness is held out against him, even as it is said: "As for the wickedness of the wicked, he shall not fall thereby in the day that he turneth from his wickedness" (Ez. 33.12). Even the Day of Atonement itself atones only for those who did repent, even as it is said: "For on that day shall the priest make an atonement for you" (Lev. 16.30).