Adhyāya 159 — Dāna–Dakṣiṇā, Āpaddharma Measures, and Prāyaścitta Classifications
न धनार्थ यशो<र्थ वा धर्मस्तेषां युधिष्ठिर । अवश्यं कार्य इत्येव शरीरस्य क्रियास्तथा
na dhanārthaṃ yaśo'rthaṃ vā dharmas teṣāṃ yudhiṣṭhira | avaśyaṃ kārya ityeva śarīrasya kriyās tathā ||
Bhishma said: O Yudhishthira, their practice of dharma is not undertaken for the sake of acquiring wealth or winning fame. They act from the conviction that dharma must be done as an unavoidable duty, and likewise they perform the necessary functions of the body simply because they are to be done.
भीष्म उवाच
Dharma should be performed without ulterior motives such as wealth or fame; it is to be done because it is intrinsically obligatory—like the basic maintenance-actions of the body that one performs simply because they must be done.
In the Shanti Parva’s instruction on righteous living, Bhishma continues advising King Yudhishthira, describing the attitude of the truly virtuous: they uphold dharma as a necessary duty rather than as a means to worldly reward or social recognition.