“In deep sleep,” say the faithful of this deepest of the three great religions, “the soul rises out of the body, enters into the supreme light and thus steps forth in its real form”
Nietzsche cites and ironizes the Upanishadic doctrine that deep sleep constitutes an entry into Brahman—a unio mystica—framing it as the ultimate expression of world-weariness in Hindu soteriology.
, On the Genealogy of Morals, 1887thesis