an.6.35 Aṅguttara Nikāya (Numbered Discourses)
Things That Play a Part in Realization
“These six things play a part in realization.What six?
The perception of impermanence, the perception of suffering in impermanence, the perception of not-self in suffering, the perception of giving up, the perception of fading away, and the perception of cessation.
These are the six things that play a part in realization.”