Vedanāsutta
“Tisso imā, bhikkhave, vedanā. Katamā tisso? Sukhā vedanā, dukkhā vedanā, adukkhamasukhā vedanā— imā kho, bhikkhave, tisso vedanā. Imāsaṁ kho, bhikkhave, tissannaṁ vedanānaṁ pariññāya cattāro satipaṭṭhānā bhāvetabbā.
Feelings
“Mendicants, there are these three feelings. What three? Pleasant, painful, and neutral feeling. These are the three feelings. The four kinds of mindfulness meditation should be developed to completely understand these three feelings.