Matsya Purana — The Greatness of Mount Kārpāsa and the Rite of the ‘Kārpāsa-Śailendra’
इति कार्पासशैलेन्द्रं यो दद्याच्छर्वसंनिधौ रुद्रलोके वसेत्कल्पं ततो राजा भवेदिह //
iti kārpāsaśailendraṃ yo dadyāccharvasaṃnidhau rudraloke vasetkalpaṃ tato rājā bhavediha //
Thus, whoever offers the gift called the “Kārpāsa-Śailendra” in the presence of Śarva (Śiva) dwells in Rudra’s world for a kalpa; thereafter, in this very world, he becomes a king.
It does not discuss pralaya directly; it uses the vast time-unit “kalpa” to describe the duration of heavenly reward in Rudra-loka earned through a specific act of dāna performed before Śiva.
It promotes the householder duty of charity (dāna) performed with devotion in a sacred setting; the stated fruit—eventual kingship—frames righteous giving as a karmic cause for prosperity, status, and leadership in a future birth.
The ritual emphasis is “Śarva-saṃnidhau”—giving in Śiva’s presence (i.e., at a Śiva shrine/temple or sanctified space). The named gift “Kārpāsa-Śailendra” indicates a specific prescribed donation item/rite (likely involving cotton/cloth), highlighting Matsya Purāṇa-style cataloging of dānas and their phalas.