Furthermore, take a mendicant who, going totally beyond the dimension of nothingness, enters and remains in the dimension of neither perception nor non-perception. While a mendicant is practicing such a meditation, if perception and focus accompanied by the dimension of nothingness beset them, that’s an affliction for them. Suppose a happy person were to experience pain; that would be an affliction for them. In the same way, should perception and focus accompanied by the dimension of nothingness beset them, that’s an affliction for them. And affliction has been called suffering by the Buddha. That too is a way to understand how extinguishment is bliss.

Furthermore, take a mendicant who, going totally beyond the dimension of neither perception nor non-perception, enters and remains in the cessation of perception and feeling. And, having seen with wisdom, their defilements come to an end.

That too is a way to understand how extinguishment is bliss.”

Numbered Discourses 9.35 4. The Great Chapter The Simile of the Cow