This sūtra, renowned for its profound insights on emptiness, encapsulates a teaching by the Buddha, largely to the layman Candraprabha's queries, about the nature and practice of samādhi through conduct and understanding of emptiness, with illustrations from the Buddha's past lives, primarily delivered on Vulture Peak Mountain with a segment at Rājagṛha, concluding with Ānanda's vow to preserve the teaching.
The sūtra's first translation by An Shigao is apparently lost, but it hints at the time when the sūtra was first circulating in written form. It integrates at least two pre-existing works, including a text on the six perfections known as Mahāprajñāsamādhisūtra or Mañjuśrībodhisattvacāryā from the fifth century (chps. 27-29) and another independent chapter with Ānanda as the interlocutor (chp. 36), indicating the sūtra's composite nature through adaptation and inclusion of earlier teachings.
The sūtra's surviving translations are that into Chinese in 556 by Narendrayaśas (517–589) in ten fascicles (T. 639) and into Tibetan by Śīlendrabodhi and Chönyi Tsultrim (between 815–838) (Toh. 127). Sanskrit manuscripts that survive date from the 6th century to more recent Nepalese manuscripts. Chapter divisions that exist in Tibetan and Sanskrit differ from version to version. This summary is based on the chapter divisions in the Tibetan version translated by 84000.
The sūtra primarily goes by the titles Samādhirāja (King of Samādhis) and Candrapradīpa Samādhi (The Samādhi of the Moon Lamp). Here, it is very likely that Candrapradīpa is a variant of the name of the layman Candraprabha. It became popular in the Indian commentarial tradition but was never particularly prominent in either China or Tibet, except for in the early Kadampa and Kagyu traditions.
The titular samādhi, or meditational state, refers to a range of things. In essence, it is an encapsulation of the bodhisattva path in a state of transcendent awareness of the nature of reality as empty, but also creative and compassionate, being imbued with the ability to adapt to and serve the needs of sentient beings in working to liberate them. The samādhi, as introduced in chapter 1, features a vast set of awakened qualities and also an array of benefits for those who practice it. In its core, the samādhi can be equated with the mind of the awakening bodhisattva as well as the buddha. Therefore, it is the path to buddhahood itself, while also being the effect of that path embodied in awakened qualities.
The sūtra also uses the term "samādhi" and "meditation" in another way that might be confusing at first sight, and that is to refer to the sūtra as a whole itself. This is because the sūtra, as a discourse of the Buddha, is the medium through which the Buddha communicates the samādhi and its qualities, and therefore, in upholding and honouring this sūtra, one upholds and honours this samādhi. Therefore, when the sūtra uses the term "this samādhi" throughout, it often refers to the entire sūtra in and of itself, and by extension, the samādhi as a meditative and liberative state of mind that is taught therein. While the sūtra does not use this vocabulary, it would be safe to say that the sūtra could be equated with buddha-nature itself.
In terms of practice, the sūtra encourages conventional Buddhist conduct, especially monastic renunciation. It also encourages tranquil meditation, śamatha and vipaśyanā, the attainment thereby of transcendent patience, and the respectful upholding and teaching of the samādhi, as encapsulated in this sūtra itself. The benefits of this range all of the advantages of Buddhist practice, up to buddhahood, as well as birth in the Pure Land of Amitābha.
Setting: The Buddha is on Vulture's Peak with a great assembly of monastics and bodhisattvas.
Purpose: He is requested to give guidance on the bodhisattva path by Candraprabha Bodhisattva. This reveals the purpose of the sūtra, which the Buddha teaches is to maintain an equanimous mind and achieving the samādhi of the equality and non-discrimination of all dharmas. This samādhi encompasses all elements of the path to awakening.
2. Śālendrarāja
Once, Śākyamuni Buddha, as King Bhīṣmottara, venerated buddhas on Vulture's Peak for countless kalpas, hearing this sūtra from each of them. The last buddha was Śālendrarāja. Serving the buddhas by making offerings is an important preliminary to practising the Path.
3. Praise of the Buddha’s Qualities
The qualities of the Buddha are attainable through this sūtra, but one must not listen to the teachings without practising them. Thus, one must cultivate faith and devotion in praising the Buddha and cultivating the practice of samādhi.
4. Samādhi
One comes to be able to attain samādhi by eliminating mental defilements, and embracing virtues like correct conduct and renunication. Just like receiving medicine but not taking it, if one receives the teachings but does not practise them, one will not progress.
5. Ghoṣadatta
The advanced practitioner must forsake worldly ties and home. Just like King Mahābala who renounced home after learning that making grand offerings to Buddha Ghoṣadatta was inferior to putting the teachings into action. He eventually became the Buddha Jñānaśūra, and his disciples became buddhas called Dṛḍhaśūra.
Making offerings without notions of giver or receiver, dedicating the merit to awakening, and realising the absense of arising and ceasing, shields one from māras. Overcome obstacles to samādhi thus, by accumulating merit and purifying karma.
Master the three kinds of patience: 1) upholding Dharma with mastery of the sūtras without anger or doubt, 2) maintaining constant meditation, attaining superior powers, and 3) seeing other worlds, teaching others, receiving prophecies, but remaining unaffected by praise or blame due to understanding emptiness.
Grasp the wisdom of the non-existence of dharmas (both self and phenomena) to eliminate desire & thus suffering. Just like Buddha Abhāvasamudgata, who proclaimed the non-existence of all dharmas upon arising, echoed by worldly sounds, and his discple, Prince Mahākaruṇacintin, who attained buddhahood as Suvicintitārtha.
9. The Patience of the Profound Dharma
View all dharmas as illusory, realising profound patience, while harmonising ultimate and relative truth—being able to balance wisdom with compassionate conduct.
Candraprabha invites the Buddha into his house for alms. The Buddha transforms the city and honours all, bestowing blessings on Candraprabha, allowing him to attain various samādhis and blessings.
11. Becoming an Upholder of the Sūtra
Understanding the Dharma (as in this sūtra), is equal to making offerings to countless buddhas. The most important thing is understanding the Dharma and teaching it to others, which protects one from falling into evil paths.
12. The Training According to the Samādhi
Realise that all dharmas are empty, beyond words and names, and that without attachment one overcomes māras. This chapter describes the ineffability of the samādhi, which ultimately has a single meaning.
13. The Teaching of the Samādhi
Cultivating the samādhi involves developing a mind of equality towards all in non-conceptual natural observation, meditating in secluded places, attaining wisdom, and embodying the Buddha's conduct. As a result of attaining the samādhi, one will be immune to all harm.
Praising the Buddha, Candraprabha offers to him. The Buddha smiles and Maitreya asks why.
15. The Elucidation of the Buddha's Smile
The Buddha smiled because as a result of Candraprabha's offerings and praises, he knows that Candraprabha will, in the future, be praised by all the world. After encountering countless buddhas, he will himself become a Buddha.
16. The Past
In the distant past, the Buddha overcame illness as Prince Mati by practising this samādhi, which also makes one impervious to slander.
17. The Entranceway to the Samādhi that is Taught by Many Buddhas
The setting returns to Vulture's Peak. Earlier, the Buddha taugh this samādhi as being the way to attain buddhahood, but now, he teaches the method for attaining the samādhi directly. It is, in brief, through (1) patience, (2) morality, (3) renunciation, and (4) yearning for the Dharma. This is exemplified by King Śirībala, who renounces his throne to practise this Samādhi.
18. The Entrustment of the Samādhi
Upholding this sūtra results in (1) perfected merit, (2) protection, (3) wisdom, and (4) eloquence. Those who maintain virtuous conduct in devotion to this sūtra will be born in Amitābha's Land of Bliss.
19. The Teaching of the Inconceivable Dharma of Buddhas
Beings should inquire about and have faith in this sūtra without fear, realising the vastness of the Dharma in every pore, encompassing all realms, awakening to the Dharma like from a dream.
One should rely on good friends and teachers without distractions, like Buddha Indraketudhvajarāja, who taught that all dharmas are like the moon in water. This maintains compassionate bodhicitta.
21. The Past
In a past life, Dīpaṅkara and Śākyamuni Buddhas, as two young monks, inspire a king to protect the Dharma. Unvirtuous monks plot to kill the two, but the devas protect them and the conspirators fall into hell.
22-23. The Teaching on the Body and the Tathāgata's Body
The Buddha's true body is the Dharma body, beyond physical characteristics, seen through samādhi. The Buddha's wisdom and the Dharma body are boundless, thus bodhisattvas should transcend attachment to physicality and cultivate deep understanding of the Dharma.
24. The Inapprehensible Tathāgata
The qualities of the bodisattva and Tathāgata are inapprehensible and unfathomable, but they fit into the categories of the correct discrimination of (1) dharmas, (2) meanings, (3) definitive words, and (4) courageous eloquence. With each, they have an ultimately pure nature, but as far as one can apprehend something, that is something conditioned to which one must not get attached.
One perceives the Buddha through form (e.g. in person, images, or visualisation), but one must understand that form and non-form are inseparable—form and bodhi are inseparable. I.e., "form is emptiness, emptiness is form."
26. Rejoicing
To cultivate the samādhi, a bodhisattva must regard all beings as one's relatives. Thus one should rejoice in others merits, always helping them to generate merit and embrace right views.
27. The Benefits of Generosity
One should not be negligent in cultivating the six perfections. The first, giving has ten benefits, including overcoming stinginess, gaining wealth, being loved by the saṅgha, and becoming close to spiritual friends.
28. The Teaching on Correct Conduct
There are ten benefits of pure morality, including fulfilling omniscience, training as the Buddha did, maintaining non-regressing vows, and achieving superior samādhi.
29. Ten Benefits
There are also sets of ten benefits to the perfections of patience, diligence, meditation, and wisdom. Besides accumulating supernormal powers, one also attains the treasuries of the Buddha, Dharma, and Wisdom.
30. Tejaguṇarāja
Tejaguṇarāja Buddha was revered by King Dṛdhadatta (Śākyamuni). That Buddha taught him the illusoriness of all dharmas, karma, and the practice of this samādhi. After cultivating this samādhi extremely diligently and urgently, King Dṛdhadatta gained great rewards and divine protection, and those who do so in the same way will be born in Amitābha's Pure Land.
31. Benefits
Practising this samādhi results in wisdom, equanimity, boundless merit, and respect.
32. The Teaching on the Nature of all Dharmas
Practising this samādhi results in attianing ultimate wisdom, discipline, supernormal abilities, the ability to visit other buddhas, endurance without anger, and boundless compassion. One will embody a life of tranquil generosity, patience, and an understanding of emptiness.
33. The Benefits of Possessing the Sūtra
By realising emptiness through five unconditioned aggregates (of disicpline, samādhi, wisdom, total liberation, and perceiving the liberated state of wisdom) and practising non-attachment, with understanding of no-self, one will attain mastery over mind and body, resulting in great merit and ultimately liberation. Through faith, one can also attain birth in Amitābha's Pure Land, swiftly attaining liberation there.
34. Kṣemadatta
Kṣemadatta Bhikṣu (Śākyamuni Buddha), engaged in self-sacrifice by setting his arm alight. Inspired by this, King Śrīghoṣa and his assembly lept from their pavilion and were saved by devas, touched by their devotion.
35. Jñānāvatī
Princess Jñānāvatī sacrificed her flesh and blood to cure Bhūtamati Bhikṣu. Jñānāvatī reflects on impermanence and vows to attain Buddhahood. In this way, one should protect and not neglect Dharma teachers.
36. Supuṣpacandra
King Śuradatta brutally executed the Dharma teacher Supuṣpacandra, but he was able to atone by revering the Dharma and building stūpas. Ultimately, upholding precepts, practising dhāraṇī, and protecting the teachings leads to swift progress toward Buddhahood without encountering such suffering.
37. Teaching the Aggregate of Morality
A bodhisattva should uphold the pure aggregate of morality, serve as a guardian of the Dharma, and practice the supreme samādhi to accumulate vast merit and wisdom, benefiting all beings. By doing so, they swiftly attain bodhi, guide others towards liberation, and protect the Dharma with unwavering resolve.
38. Yaśaḥprabha
The Buddha teaches the past life story of Yaśaḥprabha (Śākyamuni) who was persecuted by jealous bhikṣus to emphasise that through patience, generosity, and the realisation of emptiness, one can uphold the Dharma even amidst adversity. The Buddha also encourages transcending worldly attachments, cultivating virtues like compassion and loving-kindness, and understanding that all dharmas are like illusions.
39. Restraint of the Body, Speech, and Mind
Bodhisattvas must perfect bodily, verbal, and mental restraint to gain unobstructed wisdom and full awakening. By maintaining pure karma, one will see the three realms as illusory, culminating in the non-discursive samādhi.
40. Conclusion
In a boundless display of cosmic quakes and celestial offerings, the Buddha extols the profound “Vaipulya” Dharma—leading innumerable beings to various levels of awakening—and, after naming it “The Entry into Great Compassion” and “The Samādhi of the Equality of the Essential Nature of All Dharmas,” he instructs Ānanda to preserve and disseminate it, inspiring universal joy.