Nibbānasappāyapaṭipadāsutta
“Nibbānasappāyaṁ vo, bhikkhave, paṭipadaṁ desessāmi. Taṁ suṇātha …pe… katamā ca sā, bhikkhave, nibbānasappāyā paṭipadā? Taṁ kiṁ maññatha, bhikkhave, cakkhu niccaṁ vā aniccaṁ vā”ti?
A Practice Conducive to Extinguishment
“Mendicants, I will teach you a practice that’s conducive to extinguishment. Listen … And what is that practice that’s conducive to extinguishment? What do you think, mendicants? Is the eye permanent or impermanent?”