The Angulimaliya Sutra belongs to the Tathagatagarbha class of sutra. This sutra is mentioned in the Mahayana Buddhist Scripture. This sutra mainly focuses on the teachings of the Buddha and explains him to be eternal.
The Mahayana Angulimaliya Sutra and the Pali Canon's Angulimala Sutta is a completely different sutra which is included in the Majjhima Nikaya.
Origins and history of Angulimaliya Sutra
Stephen Hodge mentions that the Sutras like Angulimaliya Sutra, Mahabheriharake Pairivarta Sutra, and Mahayana Mahaparinirvana Sutra were first circulated in southern India. Then the spread was towards the northwest areas being Kashmir as the central area of circulation. The Angulimaliya Sutra provides a detailed account by mentioning the points of distribution as including southern India, Bharukaccha, and Kashmir. After thorough study in this topic, Hodge came to the conclusion that there are strong grounds based on textual evidence that Mahayana Mahaparinirvana Sutra or a major portion of it along with other related texts were compiled in the Deccan during the 2nd half of the 2nd century CE. This compilation was done in the Mahasamghika environment. Later in the 6th century CE, Paramartha mentioned that the Mahasamghikas deeply respect the Angulimaliya Sutra which teaches the Tathagatagarbha.
Central Teachings in Angulimaliya Sutra
According to Michael Radich, the Angulimaliya Sutra shares with the Mahaparinirvana Mahasutra group Tathagatagarbha buddha nature preached as explicitly connected with Atma-dhatu and concealed by defilements, the eternity of the Tathagata, the secret teachings, the promotion of faith toward the teaching of tathagatagarbha, and concern with the worst sinners, including the icchantika.
The sutra is most insistent that the Tathagatagarbha and the self, both are real. The sutra denies their existence is to lapse into a state of dangerous spiritual imbalance. Thus, to seek out the Tathagatagarbha is deemed of great value.
The sutra also mentions that the Buddha teaches the Bodhisattva Manjusri about practicing the spiritual life. He explains that practicing the spiritual life is meaningful only because there is self-principle with which the quest can be rewarded.
The Buddha explains to Manjushri the reason behind the people maintain moral behavior and engage in the holy life. He takes an example of milk. He explains Manjushri the real motive behind people churning milk is to get the butter. He also mentioned that people will avoid churning water because they know that water will not produce any other substances. Hence he concludes that people maintain moral discipline and engage in the holy life just because of the existence of the Tathagatagarbha.
The Buddha further explains to Manjushri that the people who want gold, they obviously dig in cliffs or in the rocks. They don't dig in the trees to get gold. This is because they know that the gold will not be present in the trees and when they dig in the rocks they are certain that there will be gold-ore. Likewise, the people who discern the presence of the dhatu think to themselves that they shall become a Buddha. They, therefore, maintain the moral discipline and engage in the holy life. The Buddha further adds that if there were no dhatu, the holy life would have been pointless. He further adds that the water will not produce the butter if it is churned even for a billion years. Similarly, there would not be the benefit for those attached to a self who are attached to themselves, those who engage in the holy life and moral discipline but there don't have a self-principle.
The Angulimaliya Sutra is remarkable for the vigor and passion of Angulimaliya. He teaches the Dharma and for its doctrine that at heart of all beings are in one unifying principle- the buddha-dhatu or Tathagatagarbha. Most of the scholars claim that this sutra is strikingly congruent with the parts of Mahayana Mahaparinirvana Sutra.