SB 6.1.8

tasmāt puraivāśv iha pāpa-niṣkṛtau
 yateta mṛtyor avipadyatātmanā
doṣasya dṛṣṭvā guru-lāghavaṁ yathā
 bhiṣak cikitseta rujāṁ nidānavit
Word for word: 
tasmāt — therefore; purā — before; eva — indeed; āśu — very quickly; iha — in this life; pāpa-niṣkṛtau — to become free from the reaction of sinful activities; yateta — one should endeavor; mṛtyoḥ — death; avipadyata — not troubled by disease and old age; ātmanā — with a body; doṣasya — of the sinful activities; dṛṣṭvā — estimating; guru-lāghavam — the heaviness or lightness; yathā — just like; bhiṣak — a physician; cikitseta — would treat; rujām — of disease; nidāna-vit — one who is expert in diagnosis.
Translation: 
Therefore, before one’s next death comes, as long as one’s body is strong enough, one should quickly adopt the process of atonement according to śāstra; otherwise one’s time will be lost, and the reactions of his sins will increase. As an expert physician diagnoses and treats a disease according to its gravity, one should undergo atonement according to the severity of one’s sins.
Purport: 

The dharma-śāstras like the Manu-saṁhitā 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-saṁhitā 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 śāstras 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.