Matsya Purana — Manvantaras
स महात्मा शरीरस्थस् तत्रैवेह प्रवर्तते महतस्तमसः पारे वैलक्षण्याद्विभाव्यते //
sa mahātmā śarīrasthas tatraiveha pravartate mahatastamasaḥ pāre vailakṣaṇyādvibhāvyate //
That Great Self (Mahātman), though abiding within the body, functions right here, in this very life. Yet, by virtue of its distinctness, it is discerned as existing beyond the vast darkness (tamas).
Indirectly, it frames tamas (darkness/ignorance) as something to be transcended; the Self is known as beyond that “great darkness,” implying liberation is not bound by cosmic obscuration.
It supports right living with inner discernment: even while acting “in the body” and in worldly roles, one should recognize the Self as distinct from ignorance—guiding ethical, steady governance and disciplined household life.
No direct Vāstu or ritual rule is stated; the takeaway is inner contemplation (vibhāvyate) as a prerequisite for meaningful ritual—ritual without discernment remains within tamas.