Śreyas-nirdeśa (Discerning the Superior Good): Nārada–Gālava Saṃvāda
तस्मात् सत्यव्रताचार: सत्यव्रतपरायण:
tasmāt satyavratācāraḥ satyavrataparāyaṇaḥ
Therefore, one should conduct oneself in accordance with a vow of truth and remain steadfastly devoted to that very vow—making truthfulness the guiding rule of one’s life and practice.
भीष्म उवाच
Bhīṣma teaches that dharma is strengthened by making truth (satya) a disciplined vow (vrata): one should shape one’s conduct (ācāra) around truthfulness and remain unwaveringly committed to it as a life-principle.
In Śānti Parva, Bhīṣma is instructing Yudhiṣṭhira on dharma and right conduct after the war; here he emphasizes truth-vow as a foundational ethical discipline to be adopted and maintained consistently.