Matsya Purana — The Madana-Dvādaśī Vow and the Birth of the Maruts
विलिखेन्न नखैर्भूमिं नाङ्गारेण न भस्मना न शयालुः सदा तिष्ठेद् व्यायामं च विवर्जयेत् //
vilikhenna nakhairbhūmiṃ nāṅgāreṇa na bhasmanā na śayāluḥ sadā tiṣṭhed vyāyāmaṃ ca vivarjayet //
One should not scratch or mark the ground with the nails, nor with burning embers, nor with ashes. One should not be habitually prone to lying down; rather, one should remain steadily upright and avoid excessive physical exertion.
This verse does not address pralaya or cosmology; it is an ācāra (conduct) injunction focused on disciplined, respectful behavior.
It promotes self-restraint and decorum—avoiding idle, careless acts (like defacing the ground with nails, ash, or embers) and avoiding both sloth (lying about) and extremes of exertion—qualities expected of disciplined householders and leaders alike.
Indirectly, it supports ritual cleanliness and respect for sacred/household spaces: not defacing floors or smearing with ash/embers aligns with maintaining orderly, pure environments important for domestic rites and temple-like discipline.