Adhyaya 84: शिवव्रतकथनम्
Uma–Maheshvara Vrata, Shula-dana, and Month-wise Ekabhakta Vrata
पौर्णमास्याममावास्यां वर्षमेकमतन्द्रिता उपवासरता नारी नरो ऽपि द्विजसत्तमाः
paurṇamāsyāmamāvāsyāṃ varṣamekamatandritā upavāsaratā nārī naro 'pi dvijasattamāḥ
โอผู้ประเสริฐในหมู่ทวิชะ ในวันเพ็ญและวันเดือนดับ ตลอดหนึ่งปีเต็ม หญิง—และชายก็เช่นกัน—ผู้ไม่ประมาทและตั้งมั่นในอุปวาส (การถือศีลอด)
Suta Goswami
It prescribes a year-long discipline of fasting on Pūrṇimā and Amāvāsyā as a purificatory vrata that supports Śiva-pūjā and ripens the devotee for Śiva’s anugraha (grace).
Śiva is implied as Pati—the liberating Lord—whose grace is approached through steadiness (atandritā) and self-restraint, weakening pāśa (bondage) that constrains the paśu (individual soul).
Upavāsa as a vrata: periodic fasting on lunar junctions (full and new moon) for a year, a tapas-oriented practice aligned with Shaiva observance and preparatory to deeper Pāśupata discipline.