ब्रह्मकृत-ईशानस्तवः तथा विश्वरूपदेवी-प्रकृतिरहस्योपदेशः
दिव्यवर्षसहस्रान्ते उपासित्वा महेश्वरम् धर्मोपदेशमखिलं कृत्वा योगमयं दृढम्
divyavarṣasahasrānte upāsitvā maheśvaram dharmopadeśamakhilaṃ kṛtvā yogamayaṃ dṛḍham
At the completion of a thousand divine years, having worshipped Mahēśvara, he delivered the entire instruction on Dharma and established a firm discipline suffused with Yoga—directed toward Pati, who frees the paśu from the pāśa.
Suta Goswami (narrating the Purana to the sages; reporting an internal teaching after prolonged worship of Shiva)
It links prolonged upāsanā of Mahēśvara with the fruit of complete dharma-instruction and a steady yogic regimen, implying that Linga-centered worship matures into disciplined realization rather than mere ritual.
Shiva is implied as Mahēśvara—the Pati—worthy of sustained upāsanā, who becomes the source of dharmopadeśa and yogic firmness that leads the paśu toward release from pāśa.
A long-term regimen of upāsanā (devotional worship/attentive service) culminating in a ‘yogamaya dṛḍha’ discipline—consistent with Pāśupata orientation where worship ripens into stable yoga and inner restraint.