MN 1:50.1–50.5

nibbānaṁ nibbānato abhijānāti; nibbānaṁ nibbānato abhiññāya nibbānaṁ mā maññi, nibbānasmiṁ mā maññi, nibbānato mā maññi, nibbānaṁ meti mā maññi, nibbānaṁ mābhinandi. Taṁ kissa hetu? ‘Pariññeyyaṁ tassā’ti vadāmi. Sekkhavasena dutiyanayabhūmiparicchedo niṭṭhito.

They directly know extinguishment as extinguishment. Having directly known extinguishment as extinguishment, let them not conceive it to be extinguishment, let them not conceive it in extinguishment, let them not conceive it as extinguishment, let them not conceive that ‘extinguishment is mine’, let them not approve extinguishment. Why is that? So that they may completely understand it, I say.