“Bhikkhus, there are these three feelings. What three? Pleasant feeling, painful feeling, neither-painful-nor-pleasant feeling.
“Those ascetics or brahmins, bhikkhus, who do not understand as they really are the gratification, the danger, and the escape in the case of these three feelings: these I do not consider to be ascetics among ascetics or brahmins among brahmins, and these venerable ones do not, by realizing it for themselves with direct knowledge, in this very life enter and dwell in the goal of asceticism or the goal of brahminhood.
“But, bhikkhus, those ascetics and brahmins who understand these things as they really are: these I consider to be ascetics among ascetics and brahmins among brahmins, and these venerable ones, by realizing it for themselves with direct knowledge, in this very life enter and dwell in the goal of asceticism and the goal of brahminhood.” sn.iv.235