From AN 9.34:
Ven: Sariputta: “Reverends, extinguishment (Nibbana) is bliss!
Ven. Udayi: “But Reverend Sāriputta, what’s blissful about it, since
nothing is felt?”
Ven. Sariputta: “The fact that nothing is felt is precisely what’s
blissful about it.
Sukha or happiness for an unenlightened person is experienced when encountering pleasant feelings (from the ...