If he remains in that wise for a thousand years he may lose his life". Thereupon the Daityas and Dānavas, attacking Prahlāda in the mighty deep with rocks, covered thousands of yojanas therewith. And lying at the bed of the deep covered with rocks, the high-minded Prahlāda, offered thus; with undisturbed mind, his praise to the undecaying:—"Salutation unto thee, O Pundarikāsha, salutation unto thee, O thou excellent Purusha! Salutation unto thee, O thou the soul of all worlds!

In plain words: The demons pile rocks over Prahlada for thousands of miles. Lying at the bottom of the sea, he stays calm and begins to praise Vishnu, calling him the lotus-eyed one and the soul of all worlds.