Majjhima Nikaya 2:164
SUJATOIdha, bhikkhave, bhikkhu ‘idaṁ dukkhan’ti yathābhūtaṁ pajānāti, ‘ayaṁ dukkhasamudayo’ti yathābhūtaṁ pajānāti, ‘ayaṁ dukkhanirodho’ti yathābhūtaṁ pajānāti, ‘ayaṁ dukkhanirodhagāminī paṭipadā’ti yathābhūtaṁ pajānāti.
It’s when a mendicant truly understands: ‘This is suffering’ … ‘This is the origin of suffering’ … ‘This is the cessation of suffering’ … ‘This is the practice that leads to the cessation of suffering.’