Yudhiṣṭhira’s Lament and Kṛṣṇa’s Rudra-Cosmogony Explanation (सौप्तिक पर्व, अध्याय १७)
यह सुन महादेवजी “तथास्तु” कहकर भूतगणोंके नाना प्रकारके दोष देख जलमें मग्न हो गये और महान् तपका आश्रय ले दीर्घकालतक तपस्या करते रहे
etac chrutvā mahādevaḥ “tathāstu” iti uktvā bhūtagaṇānāṃ nānāvidhān doṣān dṛṣṭvā jale magnaḥ abhavat, mahāntam ca tapaḥ āśritya dīrghakālaṃ tapasā caran avasthitaḥ.
Hearing this, Mahādeva replied, “So be it.” Then, seeing the many kinds of faults among the hosts of beings, he immersed himself in the waters and, taking refuge in profound austerity (tapas), continued his penance for a long time.
वैशम्पायन उवाच
Even when power can simply command or punish, the higher ethical response to pervasive fault is self-restraint and purification. Mahādeva’s assent (“tathāstu”) is followed by withdrawal into tapas, suggesting that moral order is restored through disciplined austerity rather than impulsive reaction.
Vaiśampāyana narrates that Mahādeva, after hearing the request or statement addressed to him, grants it with “tathāstu.” Then, noticing many defects among the bhūtagaṇas, he immerses himself in water and undertakes long-lasting austerities.