The Mahāparinirvāṇasūtra is one of the main scriptural sources for buddha-nature in China and Tibet. Set around the time of Buddha's passing or Mahāparinirvāṇa, the sūtra contains teachings on buddha-nature equating it with the dharmakāya—that is, the complete enlightenment of a buddha. It also asserts that all sentient beings possess this nature as the buddhadhātu, or buddha-element, which thus acts as a cause, seed, or potential for all beings to attain enlightenment. Furthermore, the sūtra includes some salient features related to this concept, such as the single vehicle and the notion that the dharmakāya is endowed with the four pāramitās of permanence, bliss, purity, and a self.
It may be noted that there are three different texts with similar titles in the Chinese and Tibetan canons. Of the three Tibetan texts with Mahāparinirvāṇa in their title, a short one (Derge Kanjur, No. 121) called Āryamahāparinirvāṇasūtra contains prophecies of events in the centuries after the Buddha's Mahāparinirvāṇa but has nothing on buddha-nature. Thus, this is not the Mahāparinirvāṇāsūtra which is considered as a Tathāgatagarbhasūtra. The two which deal with buddha-nature are Mahāyānasūtras and contain detailed accounts of the final teachings of the Buddha. The first sūtra, the longer one covering two volumes of Derge Kanjur (mdo sde Nya and Ta) is a translation from Chinese while the second one is a translation from Sanskrit. They appear to be two different recensions of the same original sūtra as they have similar titles and overlapping content. However, the one translated from Chinese is much longer and also contains information on the events after the Buddha entered Mahāparinirvāṇa.