Adhyaya 89: शौचाचारलक्षणम् — सदाचार, भैक्ष्यचर्या, प्रायश्चित्त, द्रव्यशुद्धि, आशौच-निर्णय
जनयत्यङ्गना यस्मान् न गच्छेत्सर्वयत्नतः चतुर्दश्यां यदा गच्छेत् सा पुत्रजननी भवेत्
janayatyaṅganā yasmān na gacchetsarvayatnataḥ caturdaśyāṃ yadā gacchet sā putrajananī bhavet
അതുകൊണ്ട് (ത്രയോദശിയിൽ) സ്ത്രീ അശുഭസന്താനത്തെ പ്രസവിക്കുന്നു, അതിനാൽ സർവ്വപ്രയത്നത്താലും ആ ദിവസം ഗമിക്കരുത്. ചതുർദ്ദശിയിൽ ഗമിച്ചാൽ അവൾ പുത്രജനനിയാകുന്നു.
Suta Goswami (narrating traditional dharma/vrata-related guidance within the Linga Purana discourse)
It links household discipline (niyama) with sacred calendrical observance; Chaturdaśī is strongly associated with Shiva-vratas, and regulating conduct on tithis is presented as supportive of purity and merit that undergird Shiva-bhakti.
Indirectly: Shiva-tattva is approached through niyama and tithi-based vrata culture—training the pashu (bound soul) to restrain impulses (pāśa) and align life with dharma, which is ultimately upheld by Pati, Lord Shiva.
A vrata-oriented niyama: observing lunar days (especially Chaturdaśī) and practicing restraint/regulated conduct as part of Shaiva household discipline rather than a technical Pāśupata yoga mudrā or āsana.