18 sins as described in Kaisika Puranam

Kaisika Puranam – Nampaaduvaan charitram is an important Srivaishana pramanam celebrated by poorvacharyas. It is enacted every year at Thirukkurungudi on the Kaisika ekadasi day.
It enshrines the story of Nampaaduvan, a chandala by birth, who, out of realization of aatma swaroopam realizes that life’s goal is eternal servitude to Sriman Narayana. He executes his atma swaroopam to perfection during his lifetime, when on a Kaisika Ekadasi day, on his way to serving the Lord with his singing skills at 3 AM in the morning before the temple doors opened, is caught by a Brahma Rakshas. Nampaaduvan assures the Brahmarakshas that he will return to it to become its prey as soon as he has completed his service to the Lord.  Brahmarakshas does not let him go. Nampaaduvan vows to return describing one sin at a time saying that may he incur such a sin if he does not return.  The 18 sins mentioned by Nampaaduvaan are each crueler than the next one, with the 18th one being the cruelest of all.

1. Based on proof, “Satyam Bhoota hitam proktam”, not being truthful. (i.e telling lies)
2. Having sexual relationship with another man’s wife (sex with married woma/en)
3. When inviting a guest of honor for having food at home, showing partiality in measure and quality of food offered to the guest v. food he himself intakes.
4. Donating a piece of land to a Brahmin and then taking it back (land grabbing from a Brahmin)
5. Enjoying the company of a woman when she is young and then leaving her in older age
6. Having sex (even with own wife) on the day of Amavasya and other occasions after performing tharpanam for ancestors.
7. Not showing gratitude to someone that has offered food.
8. Offering the hand of his daughter to someone and then backtracking on that promise.
9. Eating anything without taking bath on Sashti, Ashtami, Amavasya, and Chaturdasi. (Note that the vedic proof, ”Snaathva Bhunjeeta” requires one to consume anything only after taking bath, any day of the week).
10. Promising a donation and then backtracking on it.
11. Having sex with a friend’s wife, especially when the friend has performed an act of goodwill toward him.
12. Having sex with one’s acharyan’s wife (because acharyan is the cause of Moksha) or a King’s wife (Because the King is the cause of fulfillment of worldly desires).
13. Having married two women, showing more affection towards one than the other.
14. Leaving one’s wife, who has come to the husband in complete surrender, in her youth.
15. Obstructing the path of a herd of cattle that is rushing to drink water, out of extreme thirst.
16. Sin attributed to Brahmahatyam (killing a Brahmin) and Pancha Maha Pataham’s (Murder, theft/burglary, adultery, telling lies, betrayal).
17. Worshipping devatas other than Vasudeva (Sriman Narayanan)
18. Considering other devatas to be equal to Sriman Narayanan.