“Bhikkhus, make an exertion in seclusion. A bhikkhu who is secluded understands things as they really are.
“And what does he understand as it really is? He understands as it really is: ‘This is suffering.’… ‘This is the origin of suffering. ’… ‘This is the cessation of suffering.’… ‘This is the way leading to the cessation of suffering.’ sn.v.415
“Bhikkhus, make an exertion in seclusion. A bhikkhu who is secluded understands things as they really are.
“Therefore, bhikkhus, an exertion should be made to understand: ‘This is suffering.’… An exertion should be made to understand: ‘This is the way leading to the cessation of suffering.’”