वासिष्ठकथनम् (आदित्य–सोमवंशवर्णनम् तथा रुद्रसहस्रनाम-प्रशंसा)
रूपं त्वाष्ट्री स्वदेहात्तु छायाख्यां सा त्वकल्पयत् वडवारूपमास्थाय तपस्तेपे तु सुव्रता
rūpaṃ tvāṣṭrī svadehāttu chāyākhyāṃ sā tvakalpayat vaḍavārūpamāsthāya tapastepe tu suvratā
Daripada tubuhnya sendiri, Tvāṣṭrī menzahirkan suatu rupa bernama Chāyā. Wanita yang suci berikrar itu, dengan mengambil rupa kuda betina, melaksanakan tapa yang keras—teguh pada nazarnya—demi mencari tertib ilahi yang melonggarkan pasha (ikatan) dan memalingkan pashu (jiwa terikat) menuju Pati, Tuhan Śiva.
Suta Goswami (narrating to the sages of Naimisharanya)
It presents tapas (austerity) and vrata (vowed discipline) as the inner foundation of worship—purifying the pashu so it can approach Pati (Śiva) with steadiness, which is essential before external rites like linga-pratiṣṭhā or pūjā bear fruit.
By implying that true transformation comes through tapas that loosens pasha (bondage), it aligns with Śiva-tattva as Pati—the liberating Lord—toward whom disciplined consciousness naturally turns when impurities are burned away.
Tapas grounded in suvrata (firm vow)—a hallmark of Shaiva sādhanā and compatible with Pāśupata-oriented discipline, where sustained austerity is used to weaken bonds and stabilize devotion and insight.