The Discourse on a Certain Fruit
"When the perception of a skeleton, monks, has been developed and cultivated, one of two fruits is to be expected: final liberating knowledge in this very life; or, if there is a residue of clinging, non-returning. And how, monks, is the perception of a skeleton developed, how is it cultivated, so that one of two fruits is to be expected: final liberating knowledge in this very life; or, if there is a residue of clinging, non-returning? Here, monks, a monk develops the enlightenment factor of mindfulness accompanied by the perception of a skeleton, etc. He develops the enlightenment factor of equanimity accompanied by the perception of a skeleton, based upon seclusion, based upon dispassion, based upon cessation, maturing in release. Thus developed, monks, the perception of a skeleton, thus cultivated, one of two fruits is to be expected: final liberating knowledge in this very life; or, if there is a residue of clinging, non-returning."