Mbh 12.192.1

"'"Bhrigu said, 'Forest recluses seeking the acquisition of virtue go to sacred waters and rivers and springs, and undergo penances in lone and secluded woods abounding with deer and buffaloes and boars and tigers and wild elephants. They forsake all kinds of robes and food and enjoyments for which people living in society have a taste. They subsist abstemiously upon wild herbs and fruits and roots and leaves of diverse kinds. The bare ground is their seat. They lie down on the bare earth or rocks or pebbles or gravel or sand or ashes. They cover their limbs with grass and animal skins and barks of trees. They never shave their heads and beards or pare their nails. They perform their ablutions at regular intervals. They pour libations on the ground, as also on the sacred fire at the proper time without fail. They never enjoy any rest till completion of their daily gathering of the sacred fuel (for their homa fires) and sacred grass and flowers (for sacrifice and worship) and till they have swept and rubbed clean (their sacrificial altars). They bear without the least regard cold and heat, and rain and wind, and, therefore, the skin of their bodies is cracked all over; and in consequence of observing and laying down for themselves various kinds of rites and vows and acts, their flesh and blood and skin and bones become emaciated.[580] Endued with great patience and fortitude, they live, always practising the quality of goodness. That person who, with restrained soul, observes such a course of duties originally ordained by regenerate Rishis, burns all his sins like fire and obtains regions of felicity difficult of attainment.'