Thus I have heard: One time, the Buddha was staying at Anāthapiṇḍada’s Park in Jeta’s Grove of Śrāvastī.

It was then that the Bhagavān addressed the monks, “In this assembly, I don’t see a single thing that produces notions of desire where there are none and increases notions of the desire that have arisen … produces anger where there is none and increases anger that has arisen … produces sleepiness where there is none and increases sleepiness that has arisen … produces agitation where there is none and increases agitation that has arisen … produces doubt where there is none and increases doubt that has arisen …

“One should contemplate the foul discharges and perceptions of impurity. If one becomes distracted, then notions of desire will arise where there were none and notions of desire that have arisen will increase … anger … sleepiness … [agitation] … notions of doubt will arise where there were none and doubts that have arisen will increase.

“Therefore, monks, don’t become distracted and keep your thinking focused. Thus, monks, you should train yourselves.”

When the monks heard what the Buddha taught, they rejoiced and approved of it.