Diamond Sūtra
And again Bhagavat spoke thus to the venerable Subhuti: ‘What do you think, O Subhuti, is there anything (dharma) that was known by the Tathagata under the name of the highest perfect knowledge, or anything that was taught by the Tathagata’
After these words, the venerable Subhuti spoke thus to Bhagavat: ‘As I, O Bhagavat, understand the meaning of the preaching of the Bhagavat, there is nothing that was known by the Tathagata under the name of the highest perfect knowledge, nor is there anything that is taught by the Tathagata. And why? Because that thing which was known or taught by the Tathâgata is incomprehensible and inexpressible. It is neither a thing nor no-thing. And why? Because the holy persons? are of imperfect power.’