At Savatthī. Then a certain bhikkhu approached the Blessed One … and said to him: “Venerable sir, it is said, ‘factors of enlightenment, factors of enlightenment.’ In what sense are they called factors of enlightenment?”
“They lead to enlightenment, bhikkhu, therefore they are called factors of enlightenment. Here, bhikkhu, one develops the enlightenment factor of mindfulness, which is based upon seclusion, dispassion, and cessation, maturing in release…. One develops the enlightenment factor of equanimity, which is based upon seclusion, dispassion, and cessation, maturing in release. While one is developing these seven factors of enlightenment, one’s mind is liberated from the taint of sensuality, from the taint of existence, from the taint of ignorance. When it is liberated there comes the knowledge: ‘It’s liberated.’ One understands: ‘Destroyed is birth, the holy life has been lived, what had to be done has been done, there is no more for this state of being.’ They lead to enlightenment, bhikkhu, therefore they are called factors of enlightenment.”