Shloka 61
Adhyāya 166: Kṛtaghna-doṣa (कृतघ्नदोषः) — the fault of ingratitude and the limits of expiation
काले चतुर्थे भुठ्जानो ब्रह्मचारी व्रती भवेत् । स्थानासनाभ्यां विहरेत त्रिरह्वाभ्युपयन्नप: । एवमेव निराकर्ता यश्षाग्नीनपविध्यति
kāle caturthe bhuñjāno brahmacārī vratī bhavet | sthānāsanābhyāṁ viharet trir ahvābhyupayann apaḥ | evam eva nirākartā yaḥ agnīn apavidhyati |
ビーシュマは言った。「定められた第四の時にのみ食を取り、梵行者として戒を守り、誓戒に厳しく生きよ。日々は節制のうちに—立つか座るかして—過ごし、日に三度、浄めのために水を汲みに赴け。これこそが、聖なる祭火を捨て去った（怠った）者のための正しい贖罪である。」
भीष्म उवाच
Educational Q&A
The verse prescribes a disciplined penance: regulated eating, celibacy, vow-observance, restrained posture (standing/sitting), and thrice-daily ritual water-taking, as an expiation for neglecting the sacred household fires.
In Bhishma’s dharma-instruction in the Śānti Parva, he lays down a specific rule of conduct (austerity and purification regimen) to rectify the fault of abandoning or failing to maintain the sacred fires.