The etymological root of the Maitrayaniya Upanishad are unclear. This has historically led to a variety of names and spellings for this Upanishad.
Maitra (Sanskrit: मैत्र) and Maitri (मैत्री) are related words which literally mean "kindly, benevolent, good will, amity, friend of all creatures". The likely root for the Upanishad is probably the name of an ancient Indian scholar, Maitra, sometimes spelled Maitri or Maitreya, giving the text the alternate name of Maitri or Maitra Upanishad. The ancient scholar is also credited with a school of thought, thus giving the text the name Maitrayaniya Upanishad. Other names for this text include Maitrayani Upanishad (मैत्रायणि उपनिषद्), Maitrayana Upanishad, Maitrayaniya-brahmana Upanishad, Sriyagussakhayam Maitrayaniya-brahmana Upanishad, Maitreyopanishad and Maitrayaniyopanishad.
The Maitrayaniya Upanishad was probably composed in late 1st millennium BCE, likely after Atharva Veda texts such as the Mundaka Upanishad and Prashna Upanishad, but its precise chronology is unclear and contested. The chronology is difficult to resolve because all opinions rest on scanty evidence, an analysis of archaism, style and repetitions across texts, driven by assumptions about likely evolution of ideas, and on presumptions about which philosophy might have influenced which other Indian philosophies.
Olivelle includes Maitri Upanishad among the list of principal Upanishads that were composed last, probably around the start of the common era. Mahony suggests an earlier date, placing Prashna along with Maitri and Mandukya Upanishads, as texts that probably emerged about early fourth century BCE. Jayatilleke states, "Buddhism is not far removed in time from, though it is prior to, the Maitri Upanishad". Nakamura states that "although Buddhistic influence can be seen in the Maitri Upanishad (from words used), the particular terms and modes of expression of Mahayana Buddhism do not yet appear (in it)".
Phillips, in contrast, lists Maitri Upanishad before and about the time the first Buddhist Pali canonical texts were composed. Ranade posits a view similar to Phillips, placing Maitri's chronological composition in the fifth group of ancient Upanishads and last of the Principal Upanishads. Cowell too considers Maitri Upanishad as late era Upanishad, with its later sections comparatively modern, because of the structural and style differences within texts, inconsistencies in Poona manuscript, Calcutta (Kolkata) manuscript, Eckstein manuscript, Burnell manuscript and other manuscripts, and because some version of the manuscripts insert quotes from Vaishnavism.
Deussen states that the Upanishad is chronologically significant because its author(s) takes for granted the concepts and ideas found in Samkhya and Yoga schools of Hinduism, which must have been established by the time Maitri Upanishad was composed.
The extant recension of the text consists seven Prapāṭhakas (lessons), of which several sections are Khilas (appendices, supplements) added later. The last two are called as khila by medieval era Indian scholar Ramatirtha. Others consider the last three sections as supplements and appendices. Other discovered manuscript versions of the Maitri Upanishad present different number of sections, ranging from 1 to 4, without any appendices. There are also differences in style, structure and content among the discovered manuscripts when the text contains the same number of sections.
The text is a prose style Upanishad, with a motley collection of different sized paragraphs. The first section has four paragraphs, the second has seven, the third presents five paragraphs, while the fourth section contains six. As appendices, the fifth lesson has two paragraphs, while the sixth Prapathaka is the longest section with thirty eight paragraphs. The last supplementary section, or the seventh Prapāṭhaka has eleven paragraphs some with many sub-paragraphs.
The Maitrayaniya Upanishad is embedded after the Brahmana text of Yajur Veda, and in its opening passages refers to rituals contained therein. It contextually belongs to the Sannyasa Upanishads corpus. Hume includes it among his list of "Thirteen Principal Upanishads".
Maitri Upanishad deals with the concept and nature of Atman (Soul, Self), the question of "how is joy possible?" and "how one can achieve moksha (liberation)?"; in later sections it offers a debate on possible answers.
The text begins with the following prelude,
The performance of all the sacrifices, described in the Maitrayana-Brahmana, is to lead up in the end to a knowledge of Brahman, to prepare a man for meditation. Therefore, let such man, after he has laid those fires, meditate on the Self, to become complete and perfect. But who is to be meditated on?
The above prelude is followed by an answer, offered as a tale of a king named Brihadratha who renounces his kingdom, lives an austere life and therewith seeks the knowledge of the eternal, the soul. Sage Śākāyanya appears before the king. The king admits, "I lack the knowledge of Soul, you know the essence of Soul", so please teach me. In the resulting reply, the sage Śākāyana first claims that the "seeking the knowledge of Atman" was a practice of the past, it is difficult and not in vogue, then urges the king to ask something else". The king insists, by asking a series of metaphysical questions to the sage.
In this body infected with passions, anger, greed, delusion, fright, despondency, grudge, separation from what is dear and desirable, attachment to what is not desirable, hunger, thirst, old age, death, illness, sorrow and the rest - how can one experience only joy?
The drying up of great oceans, the crumbling down of the mountains, the instability of the pole-star, the tearing of the wind-chords, the sinking down, the submergence of the earth, the tumbling down of the gods from their place - in a world in which such things occur, how can one experience only joy!
The sage then shares with the king the philosophy of the Brahman (Universal Soul, Cosmic Principle, Ultimate Reality), described in the next lessons. Paul Deussen states that parts of the above questions, on sorrow and frailty of human life is found in the oldest Upanishads of Hinduism, for example in chapters 3.4, 3.5, 3.7, 3.28 and 4.4 of Brihadaranyaka Upanishad, yet its declamation in the question form above in Maitri Upanishad, mirrors those found in Buddhism and Samkhya school of Hinduism. It is likely, states Deussen, that these two philosophies influenced the formulation of these questions in the form presented in Maitri Upanishad.
Sakayanya answers the king's question, in verse 2.2 of Maitri Upanishad, by asserting that Atman (soul, self) exists in every individual, and it is that inmost being which "moves about without moving" (exists everywhere), which dispels darkness of ignorance and error, which is serene, immortal, fearless and soaring for the highest light. The Maitri Upanishad states that this is the message of all Upanishads,
अथ खल्वियं ब्रह्मविद्या सर्वोपनिषद्विद्या वा राजन्नस्माकं भगवता मैत्रेयेण व्याख्याताहं ते
Now then, O king, this is the Brahman-knowledge, and the knowledge contained in all the Upanishads, which was taught to us by honorable Maitri. I shall tell it to thee.
Sage Sakayanya thereafter narrates an ancient dialogue between Vālakhilyas and Prajāpati Kratu, which is sourced from Rig Veda. The dialogue states that "man was created in the image of its creator, innately has all its powers, and is driven by it". The dialogue raises a series of metaphysical objections and inconsistencies with this premise, and then offers theories to resolve the what, how and why this is so.
The Maitrayaniya Upanishad states that the Prajapati (lord of creatures) divided himself fivefold and entered all creatures of the world. The divided parts are Prana, Apana, Samana, Udana and Vyana. Prana is upward breath, Apana is downward breath (exhale). Vyana holds the Prana and Apana in balance, giving strength to the whole body. Samana is that which carries gross food to Apana and then subtler food throughout the body. Udana is that which delivers food up and down the body from what has been eaten or drunk. Together with food, Prana and Apana provide that which produces heat for the body, states paragraph 2.6 of Maitri Upanishad. The Purusha resides within, assumes the nature of Buddhi (intellect, power to reason). However, having divided itself fivefold, its purpose unattained, it impulsively feels, "let me enjoy objects". It is distracted from its purpose, its Soul. The Upanishad, thereafter recites the "parable of chariot" found in older Upanishads. Max Muller summarizes it as, "the perceptive organs are his reins, the active organs his horses, the body his chariot, the mind the charioteer, the whip being the temperament (emotions). Driven by that whip, his body goes round and round like a wheel driven by the potter. This body is made intelligent, and he (Atman) is the driver thereof." He experiences the fruits of his Karma, his personality the weaving of the three Guṇas (sattvam, rajas, tamas).
In essence, however, man seeks the true bliss, the immortal happiness, the resplendent contentment, the calm freedom that is his Soul, states paragraph 2.7 of Maitri Upanishad. This Soul of his is pure, unchanging, unmoving, undefilable, serenely calm constant, the spectator within him, the self-abiding. The Soul is inherently good, enjoyer of Ṛta (that which is properly/excellently joined, natural perfection, harmonious, holistic, right, truth).
The third Prapathaka of Maitri Upanishad presents a theory of Soul that is different than the Vedanta school of Hinduism, rather it resonates with its Samkhya school. It enumerates different types of Atman, the three Gunas and how these "qualities of personality" overwhelm him from his essential nature into egoistic life of cravings, the source of evil and sorrow in a man's life, and other terminology from the Samkhya philosophy.
The third Prapathaka opens with the question, "if soul is inherently great, then who is this soul that suffers from the 'bright and dark fruits' of karma, rebirth and is overcome by Dvandva (pairs of opposite such as heat and cold, health and disease, etc)?"
As answer, the Maitrayaniya Upanishad states that there is another, different soul, calling it Bhutatman (the elemental soul), which transmigrates. In paragraph 3.2, the Upanishad presents the "theory of gross elements and subtle elements" which combine to form Sarira (शरीर, body). The "elemental soul" resides in this body, and is overcome by prakrti guna (inner nature of an individual's personality). This, states the text, is cause of confusion, conflicting desires, unsteady behaviors and self-conceit. Man, because of this confusion, binds himself with suffering, just like a bird binds itself inside a net. Human suffering is the result of human actions (Karma) and complex interplay of human psychology (Guṇas). However, the "immortal soul" is, states the text, unaffected by the elemental soul's confusion and drifts. The third Prapathaka explains the two souls and human personalities using the metaphor of "fire, iron and forge" as follows,
He who acts, is the elemental Self; he who causes to act, is the inner man (immortal Self). Now as even a ball of iron, pervaded by fire, hammered by smiths, becomes manifold forms, thus the elemental Self, pervaded by inner man, hammered by guna (qualities, personality), becomes manifold. And as when the ball of iron is hammered, the fire is not overcome (unaffected), so the inner man is not overcome, only elemental Self is overcome.
The Maitri Upanishad in paragraph 3.4 states that true essence of man is not his body, but his immortal soul. The elemental soul is mere reflection of his Gunas (psychology), a source of his suffering, which manifests itself as quality of Tamas (darkness), such as "confusion, fear, grief, sloth, carelessness, decay, sorrow, hunger, thirst, infidelity, anger, ignorance, cruelty, meanness, envy, shamelessness, pride, folly, dishonesty, arrogance, miserliness". The quality of Rajas () too, states the Upanishad, is a result of this interplay of overpowered elemental soul and guna, and lists the manifold manifestation of this as, "greed, covetousness, craving, possessiveness, unkindness, hatred, deceit, restlessness, mania, fickleness, wooing and impressing others, servitude, flattery, hedonism, gluttony, prodigality and peevishness". While the elemental Self is thus affected, the inner Self, the immortal soul, the inner spectator is unaffected, asserts the Upanishad.
The fourth Prapathaka begins with the question, "how can the elemental Self obtain union with the true Self"?
The Maitri Upanishad answers that the elemental Self is distracted, intoxicated and attached to numerous things in life, craving for false delights, which prevents its ability to know the true Self. The remedy for elemental Self, in order to realize the true Self, is to acquire the knowledge of the Veda, perform svadharma (one's duty) based on one's age, be part of Rta, devote oneself to Ashrama stage one is in. The Upanishad, in paragraph 4.3 acknowledges the inherent tension between ascetic life of renouncing society for Self-knowledge and the svadharma in each Ashrama stage of life with devotion to society. It calls asceticism qua asceticism wrong, and then immediately calls asceticism right, necessary and praises asceticism for the inner perfection and Self-knowledge it helps bring. The fourth prapathaka does not resolve the inherent conflict it acknowledges. In paragraph 4.4, the Upanishad asserts that meditation, austerities, perseverance and knowledge leads to Brahman state, of bliss that is imperishable, infinite and unchangeable. It is this union of Brahman that frees the true Self unto bliss.
In paragraph 4.5, the Maitrayaniya Upanishad presents the question as to which of the gods is best for worship. The text answers that they are merely forms of Brahman, that one should meditate upon, worship, yet ultimately deny them and reject the gods. They are means to man's liberation, which is obtained through Soul meditation and in Self-knowledge. This is expounded on, as follows,
Hume states that the construct of the question above is notable, as it thus incorporates the three triads of thought found in ancient Indian philosophies - the Vedic trinity, the philosophical trinity in different schools of Hinduism, as well as the Brahmanic trinity.
The fifth Prapathaka then presents a motley collection of a hymn and various theories, all focussed on the pantheistic premise that everything is manifested form of Cosmic Soul, all is One Brahman-Atman.
A hymn, inserted into paragraph 5.1 and called the Kutsayana Hymn, states that the Soul (Self) is the hidden unchanging reality, the tranquil, the unlimited, the one without beginning or end. The Soul, states this pantheistic hymn, is Brahma, Vishnu, Rudra, Prajapati, Agni, Varuna, Vayu, Indra, Moon, Anna (Food), Yama, Earth. All life, all existence is manifold manifestation of the Soul. The hymn calls the Soul as Prabhu (Lord) of all pleasure and delight.
The paragraph 5.2 of the Upanishad asserts the Guna theory of Samkhya school of Hinduism. The text states that in the beginning the universe was darkness (Tamas) alone. The Brahman impelled Tamas to differentiate, thus arose passion (action qua action, Rajas). The Brahman impelled Rajas to continue differentiating, and thus arose purity (right action, truth, Sattva). These three Gunas reside in everything. The aspect of Brahman that characterizes Tamas is Rudra. The aspect of Brahman that characterizes Rajas is Brahma. The aspect of Brahman that characterizes Sattva is Vishnu. These threefold concepts have differentiated manifold into eightfold, elevenfold, into infinite number of parts, states the Upanishad. These, all creatures, and the Visva (विश्व, world, empirical universe) are manifestations of one Supreme Soul, within and without. Soul's existence is reflected by the development of goodness (virtues). It is this Soul that is reflected in man, just like sun is reflected in different vessels of water, posits paragraph 5.2 of the fifth Prapathaka.
The sixth Prapathaka enumerates soul into two, the one that is within each human being and one without that is in Sun. These correspond to two paths, one inner and one outer. The existence of inner Self can only be inferred, while the outer Self can be perceived. The outer Self is the evidence of the inner Self, and the inner Self is the evidence of the outer Self. In Paragraph 6.1, the Maitri Upanishad refers to more ancient texts of this teaching of Soul and its relation to ethical life and introspective behavior, as follows,
कश्चिद्विद्वानपहतपाप्माऽक्षाध्यक्षोऽवदातमनास्तन्निष्ठ आवृत्तचक्षुः सो अन्तरात्म
Every man who knows, free of evil, master of his senses, purified in mind, steadfast in his Self, introspective, is He (Soul, Atman).
Just like in time (kala), the solar fire ultimately consumes all beings and the outer world as food, asserts the Upanishad, it is the man's soul that consumes inner food. The outer soul and inner soul are, assuredly, states the Upanishad, one and same thing. Man should meditate on both these souls with the symbol Om (ॐ), revere them through Vyahrtis and the Savitri verse, asserts paragraph 6.2 of the text.
Om represents Brahman-Atman. The three roots (or three-footed nature) of the word are A + U + M. The sound is the body of Soul, and it manifests in three: as gender-endowed body - feminine, masculine, neuter; as light-endowed body - Agni, Vayu and Aditya; as deity-endowed body - Brahma, Rudra and Vishnu; as mouth-endowed body - Garhapatya, Dakshinagni and Ahavaniya; as knowledge-endowed body - Rig, Saman and Yajur; as world-endowed body - Bhūr, Bhuvaḥ and Svaḥ; as time-endowed body - Past, Present and Future; as heat-endowed body - Breath, Fire and Sun; as growth-endowed body - Food, Water and Moon; as thought-endowed body - intellect, mind and pysche. Brahman exists in two forms - the material form, and the immaterial formless. The material form is changing, unreal. The immaterial formless isn't changing, real. The immortal formless is truth, the truth is the Brahman, the Brahman is the light, the light is the Sun which is the syllable Om as the Self.
The world is Om, its light is Sun and the Sun is also the light of the syllable Om. Meditating on Om, is acknowledging and meditating on the Brahman-Atman (Soul, Self).
Savitri prayer and meditation with the rising sun, a means to Self worship
Anyone who loves his Self, states paragraph 6.7 of the Upanishad, loves the Savitri – literally, that which "vivifies, ray of light that enlivens knowledge". The Sun is Savitri, and thus one who loves his Soul, loves the splendor of the Sun. The text thereafter explains the meaning of Savitri verse from Rig Veda 3.62.10, its emphasis on "may the Sun inspire our thoughts, stimulate our thoughts". To think is to meditate, states paragraph 6.7 of Maitri Upanishad. To worship Sun, is to worship Self.
The sixth Prapathaka includes etymologies of six Sanskrit words, stating that these are all related to stimulating Self-knowledge. It is this Self, this Soul that is the immortal inside man, the perceiver, thinker, goer, doer, evacuator, begetter, speaker, taster, smeller, seer, hearer, toucher and all-prevader. The Soul underlies the senses yet is more than the sensory capabilities of man, it is pristine unity beyond cause, effect and action.
Knowledge is of two types, asserts the Maitri Upanishad: subjective and objective. The subjective knowledge is about the external world dependent on the person, the objective knowledge is about the Self and inner, hidden principles of the world. It is the Soul of man that comes to know subjective and objective knowledge.
The Self of man is identical with various gods and powers, it is the deities Isana, Sambhu, Bhava, Rudra, Prajapati, Visvarij, Hiranyagarbha, Satyam, Prana, Hamsa, Sastri, Vishnu, Narayana, Arka, Savitri, Dhatri, Vidhatri, Samraj, Indra, Indu and Sun. It is this Self that is to be thought after, sought after. Man should find this Self within him.
Sections 6.9 through 6.17 of the Maitri Upanishad is motley collection of three parts, all relating to the metaphysical interpretation of food. This is connected with the much older metaphorical discussion of "food" in chapter 5 of the Chandogya Upanishad. Everything is food to everything else, and taking of food is described by the Upanishad as a form of worship, a sacrifice offered by the Self to the Self.
In the first part of discussing food, the section discusses the feeding of one's own body as a form of religious ritual, and includes a hymn that is "food prayer" and that urges Atman to gratify the reciter as well as gratify all creatures in the universe. In the second part, the Upanishad calls apparent form of Brahman as food, then differentiates between food and the eater of food, and metaphorically maps food all to the nature of existence, of Prakrti (nature) and Purusha (consciousness).
In the third part, in paragraphs 6.11 to 6.17, the text states that food is the cause of all that is in space and hidden principles, then expands the idea to include time by calling Kala (Time) is the cause of food, and then celebrates Time as Brahman. Food, states the sixth Prapathaka, is the source of the world, Time is the origin of food, and Sun is the origin of Time. It symbolically maps the Time and Timeless as changing reality and the unchanging Brahman, respectively.
There is a motley collection of ideas in the discussion of Kala (Time), within the sixth Prapathaka of the Upanishad. For example, in section 6.14, it sets out to prove Time exists, acknowledges the difficulty in proving Time exists by Pramana (epistemology in Indian philosophy), then inserts a theory of inductive inference for epistemological proof as follows,
The section includes the concept of Time and non-Time, calling these as two forms of Brahman, mirroring the Upanishad's earlier discussion of Material and non-Material universe. It defines non-Time as "what was there before the appearance of Sun", and Time as "what began with the appearance of Sun". Non-Time is indivisible, Time is divisible. Year is the Murti (idol) of time. Time ripens everything, asserts the Upanishad. Sun is the foundation for Time, Sun is the Self (the Atman) of Brahman. The Brahman is the eternal, the boundless, the unborn, the immeasurable, the infinite, that which existed before Time, the light in the Sun, the colors in the smokeless fire, and all are only that one, one alone.
Appendix: Yoga, Samkhya and Vaishnava doctrines - Sixth Prapathaka
Sections 6.18 through 6.30 of the Maitri Upanishad is another motley collection of various theories. The supplementary section starts with the theory of Yoga, as the way by which the highest human goal of Self-knowledge can be attained. Paul Deussen states that this highest goal is the knowledge of Atman (Soul, Self, one's inmost being), and with that knowledge realized, becoming one with the Atman. Along with Katha Upanishad and Shvetashvatara Upanishad, the Maitri Upanishad offers one of the oldest known descriptions of Yoga theory. The sixth Prapathaka enumerates six limbs, a shorter list than the eight limbs of Patanjali's Yogasutra. The identified Yoga steps for Self-knowledge in Maitrayaniya Upanishad are: Pranayama (regulation of breath), Pratyahara (withdrawal of senses inwards), Dhyana (meditation), Dharana (concentration of mind on one idea), Tarka (creative, contemplation of idea), Samadhi (absorption with the idea, a state of being one with the idea).
After enumerating the sixfold yoga, the Upanishad states that the path to Self-knowledge is yogic meditating on Self and Brahman. This meditation leads to the state that "unites everything in the eternal, highest Atman". The one who thus knows Atman, asserts the text, becomes innately one of goodness, liberated, limitless, blissful.
In section 6.23, the Upanishad re-asserts that Brahman is the syllable Om, and then adds that Brahman is manifested in the name of Vishnu, recommending the worship of both. In section 6.30, the Maitri Upanishad acknowledges a debate, based on the Samkhya theories, whether it is the Prakrti or Purusha who attains moksha. The text asserts that it is Purusha, because man by default is controlled by his senses and mind, all emotions such as fear and bashfulness are products of a mind in bondage; man is what his mind is, and for freedom (moksha) man needs to recognize and know his soul.
In section 6.31, the Maitri Upanishad acknowledges concepts, such as Sūnya (voidness) found in Buddhism, in a form that suggests a challenge to its premise, as follows,
कतम आत्मेति योऽयं शुद्धः पूतः शून्यः शान्ता...
You ask: Which of them is Atman? (Answer:) He who has been described as pure, clean, void, quite...
The text answers that Soul exists, that reason, steadfastness, recollection, consciousness are related to Soul, as plants are related to seeds, as smoke is related to flame and sparks to fire. The Soul (Atman), states the Upanishad, is the source of all life-forces, all worlds, all the Vedas, all gods, all beings, all knowledge, all nature, all literature, all sciences, all explanations, all commentaries, it is in everything. The Upanishad (secret meaning) of the Soul is that "it is the Reality of the realities".
The goal of meditation, states Maitri Upanishad in section 6.34, is to reach liberation and tranquility of mind through Self-realization. This liberation is achieved through one's mind, by refining one's thoughts, through knowing Atman. The text includes a hymn, which in abridged form expresses these ideas as follows,
The mind of man, states the Upanishad, is the cause of his bondage and his freedom. The one whose mind is controlled by objects of sense is unfree, the one whose mind is guided by his soul is free (mukti).
The seventh Prapathaka of Maitrayaniya Upanishad states that the Soul is "the inmost being of everything", it is unlimited and it is manifestation of one Brahman. It is Soul, it is deep, it is pure, it is brilliant. The Soul is tranquil, it is fearless, it is sorrowless, it is indescribable joy. It is intelligent, it is patient, it is truth, it is harmony. It is self-dependent, it is steadfast, it is immortal, it is without limits. It is Vishnu, it is Shiva, it is Aditya, it is Indra. It is everywhere, it is in creatures, it is in nature, it is in music. It is in gods, it is in seasons, it is in planets, it is in hymns. It is the Self, it is the Lord, it manifests in many, they are all one and the same.
The final supplement of the Maitri Upanishad is a polemic against philosophies that declared antagonism to the Vedic teachings and its doctrine of soul. The section does not name any specific philosophy, but scholars have included Carvakas and Buddhism among the likely candidates. Paul Deussen states that the description though probable, is not concrete enough to prove that this section targets Buddhism. Max Muller expresses stronger doubts that the target was Buddhism. Jayatilleke, on the other hand, states that Buddhism is the likely target.
The paragraph eight of seventh Prapathaka opens by stating that there are hindrances to knowledge, and it is false teaching by those who continually beg, preach hedonism, wear red robes, ear rings and skulls, rogues as religious mendicants, who "for a price, offer that they can remove the evil influences of spirits, demons, ghosts, goblins and the like". In this group of false teachers, are others who misrepresent Vedas, have developed the strategy of deceptive circular arguments, false claims, faulty reasoning and irrational examples against the Vedic literature. All false teachers declare good to be evil, evil to be good, knowledge to be ignorance, and ignorance to be knowledge. They compel a dharma that destroys Vedas and other Sastras (scriptures, sacred books). One must not associate with these people, states the text, because they are robbers and love to oppress the believers in the Veda. The text quotes a passage to express its sentiment as follows,
In sections 7.9 and 7.10, the Upanishad refers to Katha Upanishad, and recommends that man should seek to know both knowledge and non-knowledge, the real and the delusion, the truth and untruth. Don't be "like blind men led by one who is himself blind", states the Maitri Upanishad.
The Maitri Upanishad shows signs of influence, or at least awareness of Buddhist teachings. Rhys Davis, about a 100 years ago, stated that Maitri Upanishad is the earliest Sanskrit literary usage of the term 'samadhi', a word also found in early texts of Buddhism. However, the concept of meditation and union is far older than the known literally use of the term Samadhi. The idea of "union", expressed with terms such Samadhi-root or related words, occur in Brihadaranyaka Upanishad, the oldest and longest Upanishad of the Hinduism. There are many other words and ideas that are shared between Maitri Upanishad and earliest known Buddhist texts.
Maitri Upanishad explicitly mentions, in seventh Prapathaka, a sect of thought whose teachers wear "reddish robe" (kasaya–), who deny the "existence of soul, self" premise (nairatmyavada–), preach a "dharma destructive of Vedas and Upanishads" (vedadisastra himsaka dharmabhidhyanam–) and whose goal is hedonistic "attainment of pleasure" (ratimatram phalam asya–). This sect reference could potentially be Carvakas, Ajivakas, Buddhism, Jainism or another unknown sect of thought that existed in ancient India. Jayatilleke states that this reference in Maitri Upanishad is likely to be to the Buddhists since,
- Ajivikas or Jainism upheld the belief in soul, which the Buddhists explicitly rejected
- Carvakas did not value dharma, while Buddhists were referred to as dharmavadin by opposing schools of thought.
- Buddhists were strongly accused of being hedonists at this time.
- Dhammapada seems to regard red robes as a distinct attire of Buddhist monks.
Jayatilleke additionally notes that there are many words as well as ideas such as the contemplation of the organic substances of the body and brahma-kosa theory in the sixth Prapathaka of this Upanishad that has "a Buddhist flavor".
Despite the similarities in words and some ideas, the teachings in the Upanishads of Hinduism, including Maitrayaniya Upanishad, however, are founded on the premise that "the Soul, Self and Brahman exists", and these texts discuss the paths to know, realize one's Soul (Self) and Brahman. This makes the fundamental premise of Maitrayaniya and other Upanishads of Hinduism distinctly different than Buddhism's key premise that there is "no Self, no Soul".
The Maitri Upanishad is oft cited text in comparative studies of Buddhism and Hinduism, as well as the likely influence of one on the other. Monier-Williams referred to Maitrayaniya Upanishad, among other Vedic literature, in his review of the relationship between Hinduism and Buddhism.
In studies on the earliest discussion of Yoga theory, Maitri Upanishad is among the most referred to.