Anuśāsana-parva Adhyāya 112: Dharma as the sole companion; karmic witnesses; rebirth sequences
Bṛhaspati–Yudhiṣṭhira Saṃvāda
समारोपितशौचस्तु नित्यं भावसमाहित: । केवलं गुणसम्पन्न: शुचिरेव नर: सदा,जो सदा शौचाचारसे सम्पन्न, विशुद्ध भावसे युक्त और केवल सदगुणोंसे विभूषित है, उस मनुष्यको सदा शुद्ध ही समझना चाहिये
samāropitaśaucas tu nityaṁ bhāvasamāhitaḥ | kevalaṁ guṇasampannaḥ śucir eva naraḥ sadā ||
Bhishma said: A person who has taken up and established purity as a constant discipline, whose inner disposition is steadily collected and well-composed, and who is adorned solely with good qualities—such a person should always be regarded as truly pure.
भीष्म उवाच
True purity is defined by steady inner composure and consistent virtuous conduct; one who is continually established in śauca, with a well-collected mind and good qualities, should be considered genuinely pure.
In the Anuśāsana Parva, Bhishma is instructing Yudhiṣṭhira on dharma and right conduct. Here he clarifies the criterion of purity, shifting emphasis from mere external observance to inner disposition and ethical qualities.