परिव्राजक-आचारः (Conduct of the Wandering Renunciant) — Mahābhārata, Śānti-parva 269
चतुर्थोपनिषद् धर्म: साधारण इति स्मृति: । संसिद्धै: साध्यते नित्यं ब्राह्मणैर्नियतात्मभि:,तुरीय ब्रह्मसे सम्बन्ध रखनेवाली जो उपनिषद्-विद्या है, उसकी प्राप्ति करानेवाले शम, दम, उपरति, तिततिक्षा, श्रद्धा तथा समाधानरूप जो धर्म हैं, वह सभी वर्ण और आश्रमके लोगोंके लिये साधारण हैं--ऐसा स्मृतिका कथन है। परंतु जो संयतचित्त और तपःसिद्ध ब्रह्मनिष्ठ पुरुष हैं, वे ही सदा उस धर्मका साधन कर पाते हैं
caturthopaniṣad dharmaḥ sādhāraṇa iti smṛtiḥ | saṃsiddhaiḥ sādhyate nityaṃ brāhmaṇair niyatātmabhiḥ ||
Kapila said: “The discipline connected with the ‘fourth’ (turiya) Upaniṣadic realization is, according to Smṛti, a common (universal) dharma. Yet it is steadily accomplished only by those Brahmanas who are self-restrained and perfected through austerity—men firmly established in Brahman—who alone can continually practice and fulfill that path.”
कपिल उवाच
Upaniṣadic realization (turiya/Brahman-oriented knowledge) is presented as a universal dharma in principle, but in practice it is consistently attainable only by those who have strong self-restraint and spiritual maturity—disciplined aspirants perfected by tapas and steadiness of mind.
In the Śānti Parva’s instructional dialogue, Kapila is explaining a hierarchy of spiritual practice: although the highest contemplative discipline is said to be ‘common’ to all, its sustained observance and fruition require exceptional inner control and accomplished ascetic-spiritual preparation.