Srimad Bhagvata Mahapurana: Book 6: Chapter 1: Verses 1-12
The king (Pariksit) said : The path of Nivrtti (cessation from worldly activity)has been duly delineated by your revered self, following which final beatitude (in the form of non-return to this world) is attained along with Brahma (the creator) when He (Brahma) has been reached by gradual stages (such as the attainment of the abode of the fire-god). And the path characterized by worldly activity has also been described (by you in Book Ill), O (venerable) sage-the path which has for its goal (the attainment of) heavenly and other sense-delights (the product of the three Gunas) and which leads to repeated embodiment through the (same) Gunas (for the enjoyment of such pleasures) in the case of the Jivas on whom Prakrti has not ceased her hold. The various regions of hell, which are symbolic of unrighteousness, have also been depicted by you. And so has been told at length (by you in Book IV) the story of the first Manvantara, over which presided (the Manu called) Swayambhuva (son of Brahma, the self-born), and so the posterity of Priyavrata and Uttanapada as well as the story of (both) these kings. You have also narrated how the almighty Lord brought into existence the (seven) Dwipas (the principal divisions of the earth's surface) and (as many) oceans, as well as the mountains and rivers, gardens and trees, the disposition of the terrestrial globe-with (special) reference to its divisions, their distinctive character and extent-and (likewise) of the luminaries and the subterranean regions. Now be pleased to explain to me, O highly blessed one, how a man in this world can (manage to) escape from hell, full of various horrible tortures. Sri Suka replied : If a man does not atone during his very lifetime and in the proper way (as laid down in the scriptures such as Manusmrti) for sins committed (by him) with his mind, speech and hands (body), he inevitably and actually goes after death to the infernal regions, that have already been described by me to you, and which are provide with means of severe torments. Therefore, with a body not (yet) incapacitated (for penance), one should take prompt measures here, even before death, for the atonement of one's sins, after weighing the gravity and lightness of the crime, just as a physician who knows the cause of maladies would adopt prompt remedies before it is too late, duly considering the seriousness or mildness of a complaint.
The king said : Since a man, though knowing a sin to be hurtful to his self on the testimony of what is actually seen and heard of by him, repeats it (even after atoning for it), having lost control (over his self), how could there be (any) atonement (for his sins) under the circumstances (so long as the sinful propensity is there)? Now he is absolved from a sin and now he does it again. Such being the case, I account (all) atonement fruitless like the bath of an elephant (which throws dust on its body immediately after it has washed itself). Sri Suka replied : Indeed the counteraction of a (sinful) act through (another) action (by way of penance) is not accepted as radical (since there is every possibility of a man's falling back into sin even after the process of expiation has been undergone, so long as he is identified with the body), the ignorant (those identified with the body) alone being qualified for it (the expiatory process). Self-knowledge (alone) is (therefore) the (true) atonement (for it is knowledge alone which eradicates ignorance, the root of sin), Maladies do not actually attack him who eats only wholesome food. In the same way, he who practises self. discipline, O king, gradually becomes qualified for blessedness (final beatitude).