大般若波羅蜜多経 巻四十 (Mahaprajnaparamita Sutra Vol. 40)

...and even the feelings born from the condition of mind-contact, are fast-perishing, do not arrive, and are characterized by departure; this is the time of practicing Prajnaparamita.

Shariputra, you should know that this is how a Bodhisattva Mahasattva a great being dedicated to achieving enlightenment for all possesses the upaya-kaushalya skillful means while practicing the Prajnaparamita.

Why is this so, Shariputra? The mind-realm and the nature of the mind-realm are empty. The dharma-realm, the consciousness-realm, and the feelings born from the condition of mind-contact are also empty. Shariputra, this mind-realm is empty; the mind-realm itself is the emptiness of the mind-realm. It is not separate from the mind-realm; all feelings of the mind-realm are also like this.

Shariputra, when a Bodhisattva Mahasattva possesses skillful means while practicing the Prajnaparamita, they do not engage with the earth-element, water-element, wind-element, emptiness-element, or consciousness-element. They do not engage with the marks of the earth, wind, emptiness, or consciousness elements; such is the practice of Prajnaparamita.

They do not engage with the earth-element as "constant" or "inconstant," do not engage with the earth-element as "suffering" or "pleasurable," and do not engage with the earth-element as "self" or "no-self"; such is the practice of Prajnaparamita.

They do not engage with the water, wind, emptiness, or consciousness elements as "constant" or "inconstant," do not engage with them as "suffering" or "pleasurable," and do not engage with them as "self" or "no-self"; such is the practice of Prajnaparamita.

They do not engage with the earth-element as "pure" or "impure," and so on, until the practice of Prajnaparamita. They do not engage with the water, wind, emptiness, or consciousness elements as "pure" or "impure," and so on, until the practice of Prajnaparamita. They do not engage with the earth-element as "empty" or "not-empty"... [text continues in repetitive pattern].