Matsya Purana — The Sarasvata Vrata: Vow for Sweet Speech
अभेदश्चापि दम्पत्योस् तथा बन्धुजनेन च आयुश्च विपुलं पुंसां तन्मे कथय माधव //
abhedaścāpi dampatyos tathā bandhujanena ca āyuśca vipulaṃ puṃsāṃ tanme kathaya mādhava //
Tell me, O Mādhava, how unbroken harmony may abide between husband and wife, and likewise with one’s kinsfolk—and how men may attain abundant longevity.
This verse does not address pralaya directly; it shifts the dialogue to dharma in ordinary life—specifically social concord and the means to long life.
It frames a core dharma concern: maintaining unity within marriage and among relatives. For a householder, this is foundational to social stability; for a king, such harmony in families supports order in the realm and reduces conflict.
No explicit Vāstu/temple-architecture rule appears in this verse; it functions as a question introducing ethical instruction on harmony and longevity rather than ritual or building procedure.