Matsya Purana — Prayaga Mahatmya Begins: Yudhishthira’s Remorse
किं पुना राजधर्मेण क्षत्रियस्य विशेषतः तदेवं हृदयं कृत्वा तस्मात्पापं न चिन्तयेत् //
kiṃ punā rājadharmeṇa kṣatriyasya viśeṣataḥ tadevaṃ hṛdayaṃ kṛtvā tasmātpāpaṃ na cintayet //
How much more so in the case of royal duty—especially for a kṣatriya! Having thus made one’s heart steadfast, one should therefore not brood over sin in the rightful performance of one’s duty.
This verse is not about pralaya; it belongs to the Rajadharma teaching and focuses on the ruler’s duty and the proper mental stance when performing necessary royal actions.
It states that royal duty is a special case: when a kṣatriya performs actions required by rājadharma (such as punishment, warfare, or enforcement), he should keep firm inner resolve and not be consumed by guilt, provided the action is dharmic and not driven by personal hatred or greed.
No vastu, temple-building, or ritual procedure is mentioned here; the takeaway is ethical—steadfastness of mind in the rightful execution of kingly duties.