If one commits a sin, one has to atone for it. This is known as prayaschitta. If one does not atone for the sins that one has committed, it is the king’s duty to punish the sinner.
If one drinks from a well where the dead body of an animal has been floating, one has to fast for three days. The worst possible sins are the killing of brahmana, the drinking of wine and theft. Other sins are criticising the Vedas, the bearing of false witness, killing a friend, killing a cow, forsaking one’s parents or sons, the selling of ponds, murder, lying, killing animals and the cutting down of green trees for fodder.
A killer of a brahmana has to build a hut in the forest and live there for twelve years. He has to beg for a living and give up all that he possesses to another brahmana. A killer of cows has to live on just coarse grain for a month. He has to live with cattle and follow them around during the day. All his possessions have to be given up to a brahmana and he has to bathe in cow’s urine for two months.
If a brahmana steals gold, he should go and report his crime to the king. The king will then hit him with a club and this will be the brahmin’s prayaschitta.
The sin of killing kshatriya is one-fourth the sin of killing a brahmana. If one kills a vaishya, the sin is one-eighth the sin of killing a brahmana. And if one kills a shudra, the sin is one-sixteenth of the sin of killing a brahmana. Killing a cat, a mongoose, a frog, a dog, a lizard or a crow is as sinful as killing a shudra.