[645] Setting at Sāvatthī. Bhikkhus, the perception of a skeleton (aṭṭhikasaññā), when developed and cultivated, leads to a great sense of urgency (saṃvega). And how, bhikkhus, is the perception of a skeleton developed, how is it cultivated, so that it leads to a great sense of urgency? Here, bhikkhus, a bhikkhu develops the awakening factor of mindfulness accompanied by the perception of a skeleton … he develops the awakening factor of equanimity accompanied by the perception of a skeleton, dependent on seclusion, dependent on dispassion, dependent on cessation, maturing in release. When the perception of a skeleton is developed in this way, bhikkhus, cultivated in this way, it leads to a great sense of urgency.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.