LEV33 This concept (I.e. that repentance alone is not enough for atonement] is further clarified by what is stated in the Torah (this and next verses]. Our Sages, z"l, said (Kerisos 2a) that a sin-offering is brought for an act performed unintentionally, which when deliberately transgressed incurs excision. Because a sin that can cause excision is very severe, the sinner cannot achieve full atonement for transgressing it--even when performed unintentionally--until he brings a sin-offering. This is true even though he [already] confessed his sin (since without confession and repentance his sin cannot be atoned for [even] with a sin offering, as the pasuk says [Mishlei 21:27], "The offering of the wicked is an abomination") ("[The offering of the wicked] who maintain their evil ways when offering their sacrifice, for they have not returned to Hashem--this offering is an abomination" (Metzudas David).) But after the confession (i.e., with repentance) and the offering, his transgression will be atoned for, as the pasuk says (Yayikra 4:31), "The Kohen will make an atonement for him, and he will be forgiven." Reflect upon this: if one who sins unintentionally cannot attain purity after repentance until he brings an offering, then [imagine] how harsh must be the punishment of one who deliberately sins! True, his sin can find atonement through suffering, as the pasuk says (Iyov 33:19-26), "He is castigated through pain upon his bed… He beseeches God and He favors him." The pasuk further says (Mishlei 3:12), "For Hashem admonishes the one He loves, and [then], as a father a son, He will favor [him]." But there is a solution and a remedy for the sinner (i.e., other than suffering)--through [the performance of] good deeds, which shield him from the pain, as will be explained.