Mahabharata Aswamedha Parva Chapter 51:2

Mahabharata Aswamedha Parva (Anugita Parva) Chapter 51:2 Whatever is difficult of acquisition, difficult to learn, difficult to vanquish, difficult to pass through, are all achievable by penance, for penance is irresistible. One that drinks alcoholic liquors, one that slays a Brahmana, one that steals, one that destroys a foetus, one that violates one's preceptor's bed, becomes cleansed of such sin by penance well performed. Human beings, Pitris, deities, (sacrificial) animals, beasts and birds, and all other creatures mobile and immobile, by always devoting themselves to penances, become crowned with success by penance alone. In like manner, the deities, endued with great powers of illusion, have attained to Heaven. Those who without idleness perform acts with expectations, being full of egoism, approach the presence of Prajapati. Those high-souled ones, however, who are devoid of mineness and freed from egoism through the pure contemplation of Yoga, attain to the great and highest regions. Those who best understand the self, having attained to Yoga contemplation and having their minds always cheerful, enter into the unmanifest accumulation of happiness. Those persons who are freed from the idea of mineness as also from egoism and who are reborn after having attained to the fullness of Yoga contemplation, enter (when they depart from such life) into the highest region reserved for the great, viz., the Unmanifest. Born from that same unmanifest (principle) and attaining to the same once more, freed from the qualities of Darkness and Passion, and adhering to only the quality of Goodness, one becomes released from every sin and creates all things. Such a one should be known to be Kshetrajna in perfection. He that knows him, knows the Veda. Attaining to pure knowledge from (restraining) the mind, the ascetic should sit self-restrained. One necessarily becomes that on which one's mind is set. This is an eternal mystery. That which has the unmanifest for its beginning and gross qualities for its end, has been said to have Nescience for its indication. But do you understand that whose nature is destitute of qualities? Of two syllables is Mrityu (death); of three syllable is the eternal Brahman. Mineness is death, and the reverse of mineness is the eternal. Some men who are led by bad understanding applaud action. Those, however, that are numbered among the high-souled ancients never applaud action. By action is a creature born with body which is made up of the sixteen. (True) Knowledge swallows up Purusha (Self with consciousness of body). Even this is what is highly acceptable to eaters of Amrita. Therefore, those whose vision extends to the other end (of the ocean of life) have no attachment for actions. This Purusha, however, is full of knowledge and not full of action. He dies not who understands Him that is immortal, immutable, incomprehensible, eternal and indestructible—Him that is the restrained Soul and that transcends all attachments. He who thus understands the Soul to which there is nothing prior which is uncreated, immutable, unconquered, and incomprehensible even to those that are eaters of nectar, certainly becomes himself incomprehensible and immortal through these means.