Matsya Purana — Sādhāraṇa Śrāddha: General Ancestral Rite
दानप्रधानः शूद्रः स्याद् इत्याह भगवान्प्रभुः दानेन सर्वकामाप्तिर् अस्य संजायते यतः //
dānapradhānaḥ śūdraḥ syād ityāha bhagavānprabhuḥ dānena sarvakāmāptir asya saṃjāyate yataḥ //
The Blessed Lord declares that for a Śūdra, charity is the foremost duty; for through giving, the fulfillment of all desired aims arises for him.
Nothing directly—this verse is ethical instruction (dharma) focused on the spiritual and worldly fruit of charity, not on pralaya cosmology.
It promotes dāna as a central virtue: householders are urged to practice regulated giving, and kings—who model dharma publicly—are expected to encourage and support charitable distribution as a means to welfare and merit.
No Vāstu or iconographic rule is stated; the ritual takeaway is that dāna itself is treated as a potent dharmic act yielding both puṇya and the fulfillment of aims.