Matsya Purana — Pitṛ Worlds
शान्तात्मानः शौचपराः सततं प्रियवादिनः भक्तानुरक्ताः सुखदाः पितरः पूर्वदेवताः //
śāntātmānaḥ śaucaparāḥ satataṃ priyavādinaḥ bhaktānuraktāḥ sukhadāḥ pitaraḥ pūrvadevatāḥ //
The Pitṛs (ancestral beings) are tranquil in spirit, devoted to purity, ever sweet-spoken, affectionate toward the devoted, and bestowers of happiness; they are the ancient deities of old.
It does not describe Pralaya directly; it defines the Pitṛs as ancient divine beings who continue to support cosmic and familial order by blessing the devoted.
It supports the householder (and king as exemplar) in maintaining śauca (purity), respectful speech, and Pitṛ-tarpaṇa/śrāddha—since the Pitṛs are portrayed as responsive to devotion and as givers of well-being.
The emphasis is ritual: purity (śauca), devotional attitude, and proper conduct are presented as key conditions for receiving Pitṛ blessings—core principles underlying śrāddha and ancestral offerings.