If a person has transgressed any one of the Torah precepts, affirmative or negative, willfully or unintentionally, he must confess before G-d, blessed be he, when repenting and turning away from his sin; for it is written: “if a man or woman commits any of the sins into which men fall…they must confess their sinful act” (Numbers 5:6-7); this means verbal confession. —
How does one confess? He says: “O Lord, I have sinned I have done evil, I have rebelled against thee and have done this… I regret now and am ashamed of my acts; I will never do it again.” This represents the essential part of confession. The more anyone confesses the more praise he deserves. Similarly, those who have to bring sin-offerings, or guilt-offerings, are not forgiven through those offerings for sins committed unintentionally or willfully unless they repent and confess, as it is written: “He must confess the sin he has committed” (Leviticus 5:5).
So too, those sentenced to death by the court and those sentenced to lashes are not forgiven through death or lashes unless they repent and confess. Furthermore, one who has injured a person or damaged his property, even though he pays what he owes him, is not pardoned unless he confesses and resolves never to commit such an offense again, as it is written: “If a man or woman commits any of the sins…” (Numbers 5:6).
At this time, when the Temple no longer exists, and we have no atonement altar, there is nothing left but repentance. Repentance atones for all transgressions. Even if a man was wicked throughout his life and repented at the end, we must not mention anything about his wickedness to him, as it is written: “A wicked man’s wickedness shall not bring about his downfall when he gives up his wickedness” (Ezekiel 33:12). Yom Kippur itself atones for those who repent, as it is written: “Atonement shall be made for you on this day” (Leviticus 16:30)