The dharma-sashtras like the Manu-samhita prescribe that a man who has committed murder should be hanged and his own life sacrificed in atonement. Previously this system was followed all over the world, but since people are becoming atheists, they are stopping capital punishment. This is not wise. Herein it is said that a physician who knows how to diagnose a disease prescribes medicine accordingly. If the disease is very serious, the medicine must be strong. The weight of a murderer’s sin is very great, and therefore according to Manu-samhita a murderer must be killed. By killing a murderer the government shows mercy to him because if a murderer is not killed in this life, he will be killed and forced to suffer many times in future lives. Since people do not know about the next life and the intricate workings of nature, they manufacture their own laws, but they should properly consult the established injunctions of the sashtras and act accordingly. In India even today the Hindu community often takes advice from expert scholars regarding how to counteract sinful activities. In Christianity also there is a process of confession and atonement. Therefore atonement is required, and atonement must be undergone according to the gravity of one’s sinful acts.
A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Sixth Canto, Chapter 01 – Text 08