Matsya Purana — Sādhāraṇa Śrāddha: General Ancestral Rite
जान्वाच्य सव्यं सव्येन पाणिनाथ प्रदक्षिणम् पित्र्यमानीय तत्कार्यं विधिवद्दर्भपाणिना //
jānvācya savyaṃ savyena pāṇinātha pradakṣiṇam pitryamānīya tatkāryaṃ vidhivaddarbhapāṇinā //
Placing the left knee down and, with the left hand, performing the proper circumambulation (pradakṣiṇa), one should then invite the Pitṛs, the ancestral manes. Holding kuśa-grass in hand, he should carry out that rite in the prescribed manner.
This verse is not about pralaya; it prescribes a precise śrāddha action—posture, circumambulation, and inviting the Pitṛs with darbha—within householder dharma.
It supports gṛhastha-dharma: the householder (and by extension a king as an exemplar) must honour ancestors through correctly performed śrāddha rites, using proper gestures and ritual implements.
The significance is ritual: kneeling/placing the knee, performing the appropriate circumambulation, and holding darbha (kuśa grass) are technical śrāddha procedures believed to sanctify the act and properly seat/invite the Pitṛs.