Daibirushana Jobutsu Jinbenkaji-kyo Sutra (Mahavairocana Sutra) (大毘盧遮那成仏神変加持経)
"Daibirushana Jobutsu Jinbenkaji-kyo Sutra," which is also called "Birushanakyo Sutra" or "Dainichi-kyo Sutra," refers to Esoteric Buddhist scriptures that are considered to have been established in or around the period of the seventh through eighth centuries.
This sutra was translated into Chinese in 724 by Zenmui (Śubhakarasiṃha, 637-735), who came to Tang from India, and by learned priests who pursued their studies in Tang. It was also translated into Tibetan in 812 by Śīlendrabodhi and dPal brTsegs. However, the original Sanskrit text has not been found. The Sanskrit title in Tibetan retranslated into Sanskrit is: Mahāvairocanābhisaṃbodhivikurvitādhiṣṭhānavaipulyasūtrendrarāja nāma dharmaparyāya ("the teachings of Buddhism named as Taishakuten of Daibirushana Jobutsu Jinbenkaji Hoto-kyo Sutra, Vaipulya Sutra").
This sutra consisted of two parts, so-called jiso (the thing-in-itself) of the Shingon sect, and the Shingon sect, but it contained very many descriptions of the jiso part, preaching manners (in the original form of) and mantra of the former Ryokai mandala (Mandalas of the Two Realms), and the ceremonies of Esoteric Buddhism. Although this part was described concretely, it is believed to have been impossible to understand the truth without direct teachings of Buddhism from a master.
Only 'the Stations of the Mind When Entering the Mantra-Gateway' is identified as being equivalent to a logical study of doctrines. Its composition followed the style of the early stage of Mahayana Sutra, which means that the Mantra-Gateway was explained and clarified through dialogues between Dainichi Nyorai (Mahavairocana) and Vajrapani (Lord of Mysteries).
The essence is the following part, in which Birushananyorai preached what Bodhi was when explaining the knowledge of everything of Nyorai (Tathagata).
Vajrapani said, "So be it, World-Honored One [honorific name for Gautama Buddha]. I am eager to listen."
The Buddha said, "The aspiration for Buddhahood is its cause, compassion is its root, and expedient means is its culmination.
Lord of Mysteries, what is Bodhi? It means to know one's own mind as it really is.
Lord of Mysteries, this is unsurpassed, perfect and full awakening, but there is not the slightest part of it that can be apprehended.
Because Bodhi has the characteristic of empty space, and there is no one to comprehend it, nor is there any understanding of it.
Because Bodhi has no characteristics.
Lord of Mysteries, all dharmas are without characteristics; that is to say, they have the characteristic of empty space...," from Chapter One of the Stations of the Mind When Entering the Mantra-Gateway
The following are above dialogues shown in a Chinese style.
佛言菩提心爲因 悲爲根本 方便爲究竟
祕密主是阿耨多羅三藐三菩提 乃至彼法 少分無有可得
何以故 虚空相是菩提無知解者 亦無開曉
The early stage of the Mahayana Sutra explained that the aspiration for Buddhahood was a 'mind to seek Bodhi,' while this sutra explained that 'Bodhi was to know one's own mind as it really is.'
The important thing is that the meaning changed significantly as above.