सूर्यरथनिर्णयः (चन्द्रस्य पक्षवृद्धिक्षयविधानम्)
ततः पञ्चदशे भागे किंचिच्छिष्टे कलात्मके अपराह्णे पितृगणा जघन्यं पर्युपासते
tataḥ pañcadaśe bhāge kiṃcicchiṣṭe kalātmake aparāhṇe pitṛgaṇā jaghanyaṃ paryupāsate
ثمّ حين يبقى شيءٌ يسير من الجزء الخامس عشر من النهار—المكوَّن من تقسيمات الزمن الدقيقة (كلا)—في الأَبَرَاهْنَة (آخر العصر)، تقف جماعات الأسلاف (بيتْرِ) عند الأدنى والباقي، مترقّبةً القرابين المقدَّمة في ذلك الوقت.
Suta Goswami
It fixes the ritual timing (aparāhṇa) when Pitṛ-related rites are effective, helping a Shaiva householder harmonize Śiva-pūjā with dharma—honoring Pitṛs while maintaining purity and order in daily worship.
Indirectly, it presents Śiva-tattva as the Lord of kāla (time): when rites are aligned with the proper divisions of time, the pashu (individual soul) reduces pasha (bondage) through disciplined observance under Pati’s cosmic order.
Ritual discipline in Pitṛ-tarpaṇa/śrāddha timing is highlighted—performing offerings in aparāhṇa, when the Pitṛs are said to be near and receptive to the rite’s subtle efficacy.