Khandogya-Upanishad: Second Prapathaka, Fourth Khanda
1. Let a man meditate on the fivefold Saman in all waters. When the clouds gather, that is the hinkara; when it rains, that is the prastava ; that which flows in the east, that is the udgitha; that which flows in the West, that is the pratihara; the sea is the nidhana.
2. He does not die in water, nay, he is rich in water who knowing this meditates on the fivefold Saman as all waters.