Adhyāya 166: Kṛtaghna-doṣa (कृतघ्नदोषः) — the fault of ingratitude and the limits of expiation
पतितै: सम्प्रयोगाच्च ब्राह्णीयोनितस्तथा । अचिरेण महाराज पतितो वै भवत्युत
patitaiḥ samprayogāc ca brāhmaṇī-yonitas tathā | acireṇa mahārāja patito vai bhavaty uta ||
Bhishma said: “O great king, by associating with the fallen, and likewise by sexual union with a Brāhmaṇī while being outside the Brāhmaṇa order, a man quickly becomes ‘fallen’—one who has slipped from the standards of dharma.”
भीष्म उवाच
The verse warns that deliberate intimacy with morally fallen people and prohibited sexual conduct (especially crossing prescribed social-religious boundaries) quickly leads to one’s own fall from dharma—ethical decline is portrayed as contagious through company and action.
In Śānti Parva, Bhīṣma instructs King Yudhiṣṭhira on dharma after the war. Here he lists behaviors that rapidly cause ‘patitatva’ (loss of moral/religious standing), emphasizing the consequences of corrupt association and transgressive sexuality.