There is no original sin you have come here to expiate for.
If there is any sin at all, it is ignorance.
Superstition and ego these two are, in your language, the great sins. Before all else, you have to obtain release from the hands of these two. Your Kali's spies (Gurus, priests) indulge in these superstitions and ego self-aggrandizement by decking themselves as spiritual intercessors for the sake of their self-interest. Therefore, to get Him you have to keep these two sins at a distance. All kinds of superstitions have kept us overwhelmed. The ones you call Guru and priest have kept you in darkness. They themselves have no clue and they will show the way to others?
The only sinners are spies of this Kali Yuga. These charlatans go about deceiving innocent fellow human beings by practicing the Guru business (religious business), by putting on deceptive garb. The Lord alone is Guru.
Good, bad, virtues, sins are all in the mind.