One of the Five Maitreya Treatises—the five texts imparted to Asanga by the bodhisattva Maitreya—the Ornament of the Mahayana Sutras (in Sankrit the Mahayanasutralamkara, often shortened to Sutralamkara) presents explanations of bodhisattva motivation, meditation, conduct, and fruition as expounded in the Mahayana sutras as well as demonstrating the superiority of the Mahayana.  In English, the verses fill about 130 pages. Quite simply, the Sutralamkara is one of the most important texts in the Mahayana and Vajrayana traditions and is immensely important for practitioners and scholars to know intimately.

So just what is this text which is quoted everywhere but few have read?

Mipham Rinpoche, paraphrasing Asanga's brother Vasubandu's student Sthiramati, says that this text:

. . .explains all the profound and extensive practices of the bodhisattvas, which can be summarized under three headings: what to train in, how to train, and who is training.

The first of these, what one trains in, can be condensed into seven objects in which one trains: one’s own welfare, others’ welfare, thatness, powers, bringing one’s own buddha qualities to maturity, bringing others to maturity, and unsurpassable perfect enlightenment.

How one trains is in six ways: by first developing a great interest in the teachings of the Great Vehicle, investigating the Dharma, teaching the Dharma, practicing the Dharma in accord with the teachings, persevering in the correct instructions and follow-up teachings, and imbuing one’s physical, verbal, and mental activities with skillful means.

Those who train are the bodhisattvas, of whom there are ten categories: those who are of the bodhisattva type, those who have entered the Great Vehicle, those with impure aspirations, those with pure aspirations, those whose aspirations are not matured, those whose aspirations are matured, those with uncertain realization, those with certain realization, those who are delayed by a single birth, and those who are in their last existence.

We have two translations of this text which both include the extensive and illuminating commentary by Mipham Rinpoche who based his long work on Sthiramati's famous commentary.

The first, The Ornament of the Great Vehicle Sutras, was translated by the Dharmachakra Translation Committee includes the annotations by Khenpo Shenga, who derived them often directly from Vasubandu's commentary.  You can read our interview with Dharmachakra's Thomas Doctor which includes a short discussion of this text.

The second is The Feast of the Nectar of the Supreme Vehicle, translated by the Padmakara Translation Group.  Ths has a very helpful introduction orienting the reader and giving important context.  It is also full of very helpful notes throughout.

Here is the translator from Padmakara, Stephen Gethin,  explaining the text.

It is hard to exaggerate the importance of this text in the Tibetan tradition. It was first translated from Sanskrit to Tibetan in the 8th century, at the time of Padmsambhava’s residence, by his disciple Kawa Peltsek. Atisha later taught it when he came to Tibet and refers to it repeatedly throughout his works.  Gampopa references it in his Jewel Ornament of Liberation. The great Sakya master Ngorchen Konchog Lhundrub refers to it repeatedly in his Three Visions: Fundamental Teachings of the Sakya Lineage of Tibetan Buddhism. Virtually all the great masters of all the Tibetan traditions studied this work and its commentaries in depth.

In short, the Sutralamkara has been central to the training of hundreds of thousands of practitioners and scholars and remains today a core component of all the curriculums in monasteries and shedras.

Below are a few more examples showing just how fundamental it is and some ways it is used in later Buddhist literature. And these are a small sampling—this text appears everywhere.

Jamgön Kongtrül brings it forth in his 10 volume Treasury of Knowledge. As an example, in Book Eight he relates how it is a core part of the Kadampa tradition, particularly the training in meditation. He then traces its lineage from Atisha's disciple Drontompa to Potawa to Langri Tampa and onwards to Tsongkhapa and into the present-day Gelug curriculum. He also uses it to prove the validity of the Mahayana.

Tsongkhapa and into the present-day Gelug curriculum. He also uses it to prove the validity of the Mahayana.

Tsongkahapa discusses the text throughout his Great Treatise on the Stages of the Path, the Lam Rim Chenmo. He uses it in the chapters for how to rely on a teacher; refuting misconceptions about meditation; on explaining the origin of suffering and emotions; the nature of the path leading to liberation, precepts and perfections; the paramita of perseverance, the perfection of wisdom, the gathering of disciples; and the various chapters on calm abiding meditation.

Longchenpa refers to it throughout his works as pointed out repeatedly in Tulku Thondup's The Practice of Dzogchen. It appears also in the recent translation of Longchenpa's Finding Rest trilogy. 

Dudjom Rinpoche brings it into his History of the Nyingma School throughout The Nyingma School of Tibetan Buddhism, in which he calls it the text that teaches “the integration of conduct and view.” He also refers to it repeatedly in A Torch Lighting the Way to Freedom when he is explaining the nature of the six perfections.

The most comprehensive work on the Nyingma tradition, the multi-volume masterwork by Choying Tobden Dorje, The Complete Nyingma Tradition, also extensively references it.

In Brilliant Moon, Dilgo Khyentse Rinpoche relates how he and his brother received the instructions on the text. He also brings it up repeatedly in Heart of Compassion, his discussion of the 37 Practices of a Bodhisattva; the power and strength of love; the perfection of wisdom; and the role emotions play to "destroy oneself, destroy others, and destroy discipline." He also mentions it in his biography of Jamyang Khyentse Chökyi Lodrö, using phrases describing the nature of bodhisattvas to show how the latter was one.

In his commentary on the 9th chapter of The Way of the Bodhisattva that appears in The Center of the Sunlit Sky, the great Kagyu master Pawo Rinpoche—the student of the 8th Karmapa and teacher to the 9th—devotes thirteen pages to the Sutralamkara explaining how the text proves the validity and authenticity of the Mahayana.