The Angulimaliya Sutra is a Buddhist scripture belonging to the Tathāgatagarbha class of sūtra, which teach that the Buddha is eternal, that the non-Self and emptiness teachings only apply to the worldly sphere (not the nirvanic), and that the tathagatagarbha (buddha-essence) is real and immanent within all beings and all phenomena. It must not be confused with the Angulimala Sutta, a completely different work included in the Majjhima Nikaya of the Pāli Canon.
The Angulimaliya Sutra consists largely of teachings by the bodhisattva Angulimala - in the immediate presence of the Buddha, under his direct spiritual influence and with his approval - on the correct understanding of Buddhist doctrine. The Sutra is most insistent that the tathagatagarbha and the self (Ātman) are real and that to deny their existence is to lapse into a state of dangerous spiritual imbalance. Thus, to seek out the tathagatagarbha - which is equated with the true Self - is deemed of great value. The Buddha teaches the bodhisattva Manjushri (traditionally, the bodhisattva given to the highest insight) that practicing the spiritual life is meaningful only because there is a 'self principle' (the tathagatagarbha or 'atma-dhatu' - 'essence of Self') with which the quest can be rewarded. He states:
Mañjuśrī, people churn milk because they understand that butter is present therein. Why do people not churn water ? Because that substance is not present there. Likewise, Mañjuśrī, people maintain moral discipline (śīla) and engage in the holy life (brahmacarya) because of the existence of the Tathāgata-garbha.
Moreover, Mañjuśrī, people who want gold and are endowed with discernment, dig in cliffs. Why do they not dig in trees? They dig in rocks where gold-ore (suvarna-dhātu) is present, but they do not dig in trees, where there is no gold. Likewise, Mañjuśrī, people who discern the presence of the dhātu [i.e., buddha-dhatu, which means buddha principle) think to themselves, "I shall become a buddha" and so maintain the moral discipline and engage in the holy life. Furthermore, Mañjuśrī, if there were no dhātu, the holy life would be pointless. Just as butter will never be produced from water even if one were to churn it for a billion years, similarly there would be no benefit for those attached to a self who engage in the holy life and the moral discipline if there were no self principle ātma-dhātu.
The sutra is remarkable for the vigour and passion with which Angulimala teaches Dharma and for its doctrine that at the heart of all beings is one unified principle: the buddha-dhatu (Buddha-nature) or tathagatagarbha. The doctrines of this sutra are also strikingly congruent with those of the much longer Mahaparinirvana Sutra.