Chandogya Upanishad 2.4

sarvāsv apsu pañcavidhaṃ sāmopāsīta megho yat saṃplavate sa hiṅkāraḥ yad varṣati sa prastāvaḥ yāḥ prācyaḥ syandante sa udgīthaḥ yāḥ pratīcyaḥ sa pratihāraḥ samudro nidhanam

Let a man meditate on the fivefold Sâman in all waters. When the clouds gather, that is the hinkâra; when it rains, that is the prastâva; that which flows in the east, that is the udgîtha; that which flows in the west, that is the pratihâra; the sea is the nidhana.

na hāpsu praity apsumān bhavati ya etad evaṃ vidvān sarvāsv apsu pañcavidhaṃ sāmopāste

He does not die in water, nay, he is rich in water who knowing this meditates on the fivefold Sâman as all waters.