नन्दिकेशावतारवर्णनम् (Nandikeśa Avatāra Varṇanam) — “Account of the Descent/Origin of Nandikeśvara”
शक्रमुद्दिश्य स मुनिस्तपस्तेपे सुदुः सहम् । निश्चलात्मा शिलादाख्यो बहुकालं दृढव्रतः
śakramuddiśya sa munistapastepe suduḥ saham | niścalātmā śilādākhyo bahukālaṃ dṛḍhavrataḥ
Aiming his austerity toward Śakra (Indra), that sage performed a most difficult tapas. Named Śilāda, steady in mind and firm in his vow, he continued for a long time without wavering.
Suta Goswami
Tattva Level: pashu
It highlights the Shaiva principle that unwavering resolve (dṛḍha-vrata) and steadiness of mind (niścalātmā) make tapas fruitful, ultimately preparing the soul (paśu) to receive higher grace beyond worldly aims.
Though the immediate intention is directed toward Indra, the Shiva Purana frames such disciplined tapas as a purifier of intention; in later Shaiva unfolding, the seeker’s focus is refined from limited deities and boons toward Saguna Shiva (often through Linga-upāsanā) and finally toward liberation.
The takeaway is sustained tapas with a firm vow—daily japa (especially the Panchakshara, “Om Namaḥ Śivāya”), regulated conduct, and steady meditation; the verse emphasizes endurance and consistency rather than a single external rite.