शिवार्चनविधिः — देवतानां पाशुपतव्रतप्राप्तिः तथा पशुपाशविमोक्षणम् (अध्याय ८०)
अथ द्वादशवर्षं वा मासद्वादशकं तु वा दिनद्वादशकं वापि कृत्वा तद् व्रतम् उत्तमम्
atha dvādaśavarṣaṃ vā māsadvādaśakaṃ tu vā dinadvādaśakaṃ vāpi kṛtvā tad vratam uttamam
Then, having undertaken that excellent vow—whether for twelve years, or for twelve months, or even for twelve days—such disciplined observance purifies the paśu (the bound soul) and turns it toward Pati, the Lord, making one fit for the higher fruit of Śiva-worship.
Suta Goswami (narrating the vrata-vidhi to the sages of Naimiṣāraṇya)
It establishes approved time-frames (12 days, 12 months, or 12 years) for a Śiva-vrata, showing that disciplined duration itself is a key limb of Liṅga-pūjā and its transforming power.
By implying that steadfast observance leads the paśu toward the supreme fruit, it reflects Śiva as Pati—the liberating Lord who receives worship and loosens pāśa (bondage) through regulated sādhana.
Vrata-anuṣṭhāna (vowed discipline) as a Pāśupata-oriented practice: fixed-term observance supporting purity, restraint, and consistent Liṅga-pūjā.