Adhyāya 166: Kṛtaghna-doṣa (कृतघ्नदोषः) — the fault of ingratitude and the limits of expiation
अल्पे वाप्यथ शोचेत पृथक् संवत्सरं चरेत् । त्रीणि श्रोत्रियभार्यायां परदारे च द्वे स्मृते
alpe vāpy atha śocet pṛthak saṃvatsaraṃ caret | trīṇi śrotriyabhāryāyāṃ paradāre ca dve smṛte ||
Bhīṣma said: “Even for a minor lapse one should feel remorse and then live apart in expiation for a full year. In the case of approaching the wife of a learned Brāhmaṇa (śrotriya), three years of such penance are prescribed; and in the case of another man’s wife, two years are remembered in the tradition.”
भीष्म उवाच
The verse teaches graded expiation (prāyaścitta) proportional to the gravity of sexual misconduct: remorse is required even for minor faults, and stricter penance is prescribed for violating protected relationships—especially involving a Veda-learned Brāhmaṇa’s wife and, more generally, another man’s wife.
In Śānti Parva, Bhīṣma instructs Yudhiṣṭhira on dharma after the war. Here he cites traditional Smṛti-based norms about remorse and periods of living apart as penance, specifying different durations depending on the offense.