Are there certain sins that nullify good deeds and others that are only nullified by repentance, and what are the sins that are expiated by good deeds and those that require repentance for their expiation?

Good deeds annul bad deeds, as stated in the Holy Quran and the Prophetic Sunnah (definition). However, the majority of scholars are of the view that this applies specifically to minor sins related to the rights of Allah Almighty. As for major sins, they require repentance, and the rights of people necessitate seeking their forgiveness. Thus, the verse "Indeed, good deeds do away with ill deeds" and the saying "Follow up a bad deed with a good deed, it will erase it," are understood by the majority to refer to the expiation of minor sins, provided that major sins are avoided. Major sins are not expiated except through sincere repentance.