The Śūraṅgama Sūtra, Volume Three: The Body's Entry into the Fundamental Tathāgatagarbha's Wonderful True Suchness Nature

Original text: 阿难。譬如有人。以一冷手。触于热手。若冷势多。热者从冷。若热功胜。冷者成热。如是以此。合觉之触。显于离知。涉势若成。因于劳触。兼身与劳。同是菩提。瞪发劳相。因于离合。二种妄尘。发觉居中。吸此尘象。名知觉性。此知觉体。离彼离合。违顺二尘。毕竟无体。

Explanation: Ānanda, for example, if a person touches one hot hand with a cold hand, and the cold force is greater than the hot force, the hot hand, infused by the cold, will become cold; if the heat is stronger, the cold hand, infused by the heat, will become hot. In this way, using the contact that occurs together with awareness, the knowing nature of separation and union is manifested. Because the two hands remain in contact for a long time, a balance of cold and hot forces is produced. Taking both the body faculty and the wearied contact together, both are wearied marks manifested from the bodhi mind through staring. Relying on the two false sense objects of separation and union, the body faculty gives rise to a knowing awareness within them, which absorbs the marks of the contact sense object; this is called the nature of knowing awareness. This body of knowing awareness, apart from those two sense objects of separation and union, and of conformity and opposition, ultimately has no self-nature of its own.

Original text: 如是阿难。当知是觉。非离合来。非违顺有。不于根出。又非空生。何以故。若合时来。离当已灭。云何觉离。违顺二相。亦复如是。若从根出。必无离合。违顺四相。则汝身知。元无自性。必于空出。空自知觉。何关汝入。是故当知。身入虚妄。本非因缘。非自然性。

Explanation: Ānanda, you should know that this knowing awareness does not come from the marks of separation and union, does not exist because of conformity and opposition, does not come out of the body faculty, and is not produced from empty space. Why is this said? If the sensation of touch arose when the body faculty and the contact sense object united, then when the body faculty and the contact sense object separated, the sensation of touch would vanish and be gone—how then could one know that the faculty and the object had separated? If the sensation of touch arose when the faculty and object separated, then when the faculty and object united, the sensation of touch would vanish and be gone—how then could one know that the faculty and object had united?

If the sensation of touch arose from one of the two marks of conformity and opposition, then it would not be aware of the other mark. If the sensation of touch came from the body faculty, then, conforming to the attributes of the body faculty, there would necessarily be no marks of separation and union, nor any marks of conformity and opposition, and it would not be aware of these marks; therefore the sensation of touch on your body originally has no self-nature of its own. If the sensation of touch came out of empty space, then empty space itself would possess the sensation of touch—what would that have to do with the body entrance, the sensation of touch of your body? Therefore you should know that the body entrance is false and illusory; it is fundamentally neither of the nature of causes and conditions nor of a natural nature, but rather the nature of the tathāgatagarbha.