To think of suffering as happiness is perverse; to think of happiness as suffering is perverse.
To think of the impermanent as permanent is perverse; to think of the permanent as impermanent is perverse.
To think of non-being as being is perverse; to think of being as non-being is perverse.
To think of the impure as pure is perverse; to think of the pure as impure is perverse.
You repeatedly cultivate these objects of cultivation without properly knowing these four perversities. You engage in meditative cultivation treating the permanent as though it were impermanent, that which has being as though it lacked being, and the pure as though it were impure. Pronouncements regarding bliss, being, permanence, and purity are found both amongst mundane people and amongst supramundane people, but these are each different. The words are mundane designations, while the meaning is supramundane wisdom (lokottara-jnana).
In order to curb the heterodox teachings, the Tathagata says that there is no atma (self), no sattva (being), no jiva (life-essence), and no pudgala (individual). The teachings about the self by the heterodox teachers are like the letters bored by chance, without understanding, by worms, and therefore I made known the teachings that all beings are devoid of a self.
Having proclaimed that the absence of self is the word of the Buddha, I also teach that there is True Being, after I have taught that all phenomena (dharmas) are devoid of self, taking the occasion into consideration regarding those who need to be trained and in order to benefit beings.
The self of the worldly, which they say is the size of a thumb or a mustard seed, is not like that. The concept of the self of the worldly is also not like that. In this way, it is said that all dharmas are devoid of self. But actually, it is not true that all dharmas are devoid of True Being. True Being is real, True Being is unchanging, True Being is virtue, True Being is eternal, True Being is unshakeable, True Being is peace.
The Tathagata teaches what is true. Let the four divisions of the assembly strive meditatively to cultivate this.
—Buddha Shakyamuni, Mahaparinirvana Sutra