Anuśāsana-parva Adhyāya 112: Dharma as the sole companion; karmic witnesses; rebirth sequences
Bṛhaspati–Yudhiṣṭhira Saṃvāda
परिग्रहाच्च साधूनां पृथिव्याश्वैव तेजसा । अतीव पुण्यभागास्ते सलिलस्य च तेजसा,पृथ्वीके कुछ भाग साधु पुरुषोंके निवाससे तथा स्वयं पृथ्वी और जलके तेजसे अत्यन्त पवित्र माने गये हैं
parigrahācca sādhūnāṃ pṛthivyāścaiva tejasā | atīva puṇyabhāgāste salilasyaca tejasā ||
Bhīṣma said: “Certain portions of the earth are regarded as exceedingly holy—made so by the presence and sanctifying association of virtuous people, and also by the inherent radiance (purifying power) of the earth itself and of water.”
भीष्म उवाच
Holiness (puṇya) increases where virtuous people dwell, and it is further supported by the purifying potency (tejas) of natural elements like earth and water; moral and spiritual quality is shaped by both noble association and purifying supports.
In Bhīṣma’s instruction (Anuśāsana Parva), he explains why certain regions are considered especially sacred: they become highly meritorious through the residence/association of sādhus and through the purifying power attributed to earth and water.