At Sāvatthi.

"Bhikkhus, cultivate collectedness. A bhikkhu who is collected discerns as it truly is. What does he discern as it truly is?

'This is suffering,' he discerns as it truly is; 'This is the arising of suffering,' he discerns as it truly is; 'This is the ending of suffering,' he discerns as it truly is; 'This is the way of practice leading to the ending of suffering,' he discerns as it truly is.

Cultivate collectedness, bhikkhus. A bhikkhu who is collected discerns as it truly is.

Therefore, bhikkhus, effort should be made to fully understand: 'This is suffering'; effort should be made to fully understand: 'This is the arising of suffering'; effort should be made to fully understand: 'This is the ending of suffering'; effort should be made to fully understand: 'This is the way of practice leading to the ending of suffering.'"