Hinduism vs Buddhism - Complementary or Contrary?

Many experts on religion have been debating and still continue to debate on the issue of Hinduism vs. Buddhism. While certain schools of thought believe that Buddhism is an offshoot of Hinduism and that the Buddha was essentially part of the Hindu pantheon, this view is not quite acceptable to Buddhists.

Of course, it is widely understood and acknowledged that Buddhism as a religion became popular in India during a revolutionary movement that took place to abolish oppression and extreme orthodoxy prevalent in the then Indian milieu.

In this article, we discuss the topic of Hinduism and Buddhism as two of India's most ancient and most popular religions, also going in-depth into their similarities and their differences.

Hinduism and Buddhism - Complementary Religions

Before proceeding further with this study, it is imperative to state that Hinduism and Buddhism are very ancient religions, both originating from the Indian subcontinent. They share a unique relationship; very similar in nature, but also apart from each other; much like Christianity and Judaism. Strangely enough, Buddha was believed to be born in a Hindu family, just like Jesus Christ was born in a Jewish family.

Buddhism in India blossomed as a result of people seeking freedom from an extremely oppressive, caste-ridden society, which stipulated strict norms of ritualistic worship, and granted special status to just a handful of the "privileged class" of society, while looking down upon the rest of the population.
Over 1,500 years ago, Hindus had accepted the Buddha as one of the ten incarnations (Dashavatara) of Lord Sri Mahavishnu. However, the rivalry between the two religions continued to grow through the centuries. Though most rulers of the princely provinces practised a policy of religious tolerance and secularism, there were stray instances where Hindu rulers persecuted Buddhists residing in that region. Rulers such as Sasank, who was a contemporary of Harshavardhana, actually went to the extent of vandalizing sacred Buddhist monuments and even burnt down the pipal tree under which the Buddha had attained nirvana.

Yet, despite the apparent differences between Hinduism and Buddhism, they also ended up influencing each other in several ways. For instance, while Mahayana Buddhism adopted the Indian methods of Bhakti or devotional worship, the Buddhist concept of compassion and ahimsa (non-violence) took its roots in the Indian psyche. The tantra shastra of Hinduism went on to create the Vajrayana school of Buddhism. Hinduism then adopted the excellent Buddhist techniques of meditation, yoga and pranayama, using them as a means to attain awareness and higher states of consciousness. Indian art and architecture too, benefitted richly from Buddhism.

Hinduism and Buddhism - Two Sides of the Same Coin

The rituals and practices of Hinduism and Buddhism have similarities and differences. While Theravada Buddhism is quite conservative, and generally closest to the early form of Buddhism, the Mahayana and Vajrayana beliefs that emerged later, are more emancipated in thought. It is believed that schools of Buddhism, at a later time, developed several other rituals that were influenced by existing religions and cultures of India, Japan, China, Tibet and Southeast Asia. However, there are also many glaring differences between the early teachings of Hinduism and those of the Buddha. These differences are evident in the recorded literature of the Pali Canon of the Theravada school of Buddhism.

The Vedic cultural theme, however, shares several similarities with Buddhism, Jainism and the more modern versions of the Buddha, Mahavira and the Brihadaranyaka Upanishad. All these were probably influenced by the North-eastern regions of India, Bihar, Uttar Pradesh and even Nepal.
It is worth mentioning here that the India of yore basically had two main philosophical streams of religious thoughts, namely, the Shramana and the Vedic. These two religions, which had always shared paralleled beliefs, had peacefully co-existed side by side for thousands of years.  Both Buddhism and Jainism are but extensions of the Shramana belief. Modern Hinduism, on the other hand, is an extension of the Vedic belief, combined with a mixture of the ancient Shramanic, folk and tribal traditions of India. The similarities between the Shramana and the Vedic religions were influenced by the Vedic priests, who were referred to as the Brahmins. These Brahmins also followed some of the Shramana teachings, thereby incorporating some of the Shramana beliefs into the Vedic's religious philosophy.

The Buddha rejected the most common religious paths to attain salvation or nirvana. According to his teachings, in order to achieve salvation, one does not have to accept the authority of the scriptures or even acknowledge the existence of God. The Buddhist texts actually describe how Buddha rejected such paths of salvation, openly condemning them as "pernicious views". It is interesting to note here that later Indian religious thoughts were influenced by this very different interpretation of the Buddhist tradition of beliefs.

Though Buddhism attained prominence in the Indian subcontinent, it eventually faded out in the 11th century CE by both Hinduism and Islam. However, Buddhism continued to grow and flourish outside of India. Tibetan Buddhism is one of the most predominant religions in the Himalayan region, while Theravada Buddhism evolved in Sri Lanka and Southeast Asia. The Mahayana branch of Buddhism is most practised in East Asia, mostly in China.

Early History of Buddhism

There is clear recorded evidence to show that both Buddhist and Hindu traditions peacefully co-existed with each other, from a very early date. The Buddha is mentioned in several of the Puranas, which are believed to have been written after his birth. Some Buddhist teachings seem to have their roots in the ideas and ideologies presented in the early Upanishads. Interestingly, these ideas are sometimes concurrent with Hindu thoughts, while some others have been criticized and re-interpreted to fall in line with Buddhist philosophy.
Some prominent Indian scholars believe that the Bhagavad Gita, which was chronicled after the birth of the Buddha, was actually written as part of the Hindu perception of Buddhism.

In later years, both Buddhism and Hinduism were supported by Indian rulers, regardless of the rulers' own religious identities. Hence, Buddhist kings revered and respected Hindu deities and teachers. Similarly, several major Buddhist temples were built under the patronage of Hindu rulers.

Similarities between Hinduism and Buddhism

Hinduism and Buddhism share many similarities with each other. Listed below are the aspects where these two religions show a remarkable semblance to each other:

Technical Terms

The Buddha had adopted many of the terms which were already very much in use in the philosophical discussions of his era. However, many of these terms go to imply a different meaning in the Buddhist tradition. We now discuss some of these terms and their implications in each of these religions.

Karma

Karma, meaning "action" or "activity", often also implies its subsequent results (also commonly referred to karma-phala, "the fruits of action"). Karma generally denotes the entire cycle of cause and effect and is described in this manner in both Buddhism and Hinduism.

Karma is a vital aspect of Buddhist teachings. In Buddhism, karma is a direct result of a person's word, thought, and action in life. Since a person's word, thought, and action form the basis for good and bad karma, sheela or moral conduct goes hand-in-hand with the development of wisdom.

The Buddha derived his teaching of the concept of karma through direct experience rather than from the pre-Buddhist culture which was in existence then. But he used the same terminology, so that the people in that particular region could relate to what taught.

Dharma

Dharma, which means "righteousness", also refers to Natural Law or Reality. In relation to its significance in religion and spirituality, it may also be considered the "Path of the Higher Truths". A Hindu appellation for Hinduism itself is Sanatana Dharma, which translates as "the eternal dharma." Similarly, the Buddha Dharma in an appellation for Buddhism.

The four main dharmas in India are Hinduism, Buddhism, Jainism or the Jaina Dharma and Sikhism or the Sikha Dharma. Hence, the dharma also formed the basis on which the religion itself rested. Each of these religions also retain the centrality of dharma in their teachings. All these religions also believe that those that live in harmony with dharma proceed more quickly towards attaining Dharma and Moksha or liberation. Dharma could also refer to religious duty, social order, right conduct, or even simply put, virtue.
It is believed that in India, the concept of reincarnation (along with karma, samsara and moksha) evolved via the beliefs of non-Aryan people outside of the caste system, whose spiritual ideas influenced later Indian religious thought. Buddhism and Jainism are hence said to be continuations of this tradition. It is further believed that the Upanishadic treatments of samsara, karma, and reincarnation are fundamentally the contributions of the Upanishads to Hinduism.

According to Hindu philosophy, the atman or the soul immortal, while the human body is subject to birth, decay, old age and death. The whole idea of reincarnation here, is intricately linked with the notion of karma, the sum-total of the good and the bad deeds performed in one's lifetime.  Also, the cycle of death and rebirth, governed by karma, is referred to as samsara.

The Shakyamuni Buddha went against the traditional Hindu theory that all beings have an immortal atman within the body. Buddhism developed an understanding of a "continuum or stream of skanda" through such disciplines as vipassana and shamata. Buddhism challenges the existence of all such entities and believes that an "evolving consciousness" is what is reborn, its qualities conditioned by karmic laws.

Symbolisms Used both in Hinduism and Buddhism

Both Hinduism and Buddhism use common symbolisms, which are listed below:

• Mudra or hand-gestures, expressing emotions
• Dharma Chakra, which appears on the National Flag of India, as also on the flag of the Thai Royal Family
• Rudraksha, or the beads that monks and devotees use for praying
• Tilak, a vermilion mark on the forehead, which is also interpreted as the Third Eye
• Swastika or Sauwastika, which is a sacred symbol that can be used both clockwise or counter-clockwise

Mantra Chanting

Buddhism uses mantras or religious syllables, basically as spiritual conduits. According to Buddhism, these specific words emit vibrations, which help the devotee gain one-pointed concentration during prayer. Other uses of the mantra include chanting in order to accumulate wealth, avoid danger and also eliminate enemies. Mantra chanting has remained the mainstay for Hinduism, Buddhism, Jainism, Sikhism and also Zoroastrianism.

Differences between Hinduism and Buddhism

Despite the many similarities between Hinduism and Buddhism, there also exists glaring differences between the two religions. The most predominant differences are as mentioned below:

The Concept of God

Though the Buddha never denied the existence of God nor forbade the worship of the popular gods in existence then, the fact remains that Buddhism does not believe in idol worship, but rather states that these gods are merely angels who may be willing to help good Buddhists. However, Buddhism does not believe that these deities are in any way guides to religion.
It would be worthwhile to mention here, that the focus of the Noble Eight-Fold Path of Buddhism is not really about worshipping god; not about achieving heaven in the next life; and not about experiencing Brahma consciousness in this life or the next. The real reason here is to break free from the suffering that each being is constantly subjected to; to experience liberation from the cycle of rebirth and experience awakening in this very life.
We all know that the Buddha himself realized this state of awakening after merely about six years of practice. He entered into the states of Sunyata, rapture, sukkha or happiness, tranquility, equanimity, bliss and the like, before eventually attaining the nirvana stage. According to the Pali Canon, he visited any realm he felt like, subsequent to that awakening. After attaining Parinirvana, the Buddha was liberated from all rebirth in this samsara.

The Buddha as depicted in the agamas, set an important trend in nontheism in the Buddhist religion. Nevertheless, in many passages in the Tripitaka, the Gods are mentioned and specific examples are given of individuals who were reborn as gods, as also of gods who were reborn as humans. Buddhist philosophy hence recognizes the various levels of gods and godliness, but none of these gods is considered the creator of the world or of the human race. This ideology is completely removed from the main tenets of Hinduism.

Later Mahayana literature, however, talks about an eternal, all-pervading, all-knowing, immaculate, uncreated and immortal Creation, the Dharmadhatu, which is inseparably linked to the Sattvadhatu, or the realm of living beings. This Dharmadhatu is the Awakened Mind (bodhicitta) or Dharmakaya ("body of Truth") of the Buddha himself; and is attributed to the Buddha in a number of Mahayana sutras and tantras as well.
According to some Mahayana texts, this principle sometimes manifests itself in different "Buddha forms", such as Samantabhadra, Vajradhara, Vairochana, Amitabha and Adi-Buddha, among several others.

Rites and Rituals Practices

According to the Pali Canon, there are several instances where the Buddha discouraged Brahmins from the practice of rites and rituals. According to him, virtue, purity of thought and word, and ethical conduct was the most important prerequisite for attaining higher states of being. According to this philosophy, the following are the best ways to practice religion:

• Going to the Buddha, the Dhamma, and the Sangha for refuge
• Observance of the Five Precepts
• Going forth from samsara and leading the holy life, resulting in the realization of extinction of asavas; that which excels all other sacrifices.

Mahayana Buddhism in Japan, Tibetan Buddhism and some other branches of Buddhism later adopted the Homa and Yagna (fire ritual) concepts of Hinduism and absorbed it in their respective cultures. These philosophies also offered prayers for ancestors and the deceased.

Caste Discrimination

While Hinduism was rife with the curse of caste discrimination, the Buddha completely went against the caste distinctions of the Brahmanical religion. In fact, the Buddha most vociferously criticized the Brahminical claims that the caste system was divine in nature, showing them that it is nothing but a mere human convention. He was hence described as a corrupter and opposed to true dharma in some of the Puranas. Buddhism openly offered ordination to all regardless of caste. In fact, the earliest texts of Buddhism gave no predominance whatsoever to caste and firmly stated that caste is not determined by karma.
The idea of ritual purity, which also provided a foundation for the caste system in Hinduism, was also entirely absent from the Buddhist monastic code, and not generally regarded as being part of Buddhist teachings.

Cosmology

According to Buddhist cosmology, there are a total of 31 planes of existence within the samsara. Living beings who reside in these realms are subject to rebirth after some period of time. Only those who are in the realm of liberation are free from this cycle of birth and death.  The Buddhas are considered to be beyond all these 31 planes of existence after parinibbana. According to Buddhist philosophy, while the Hindu God, Brahma, is in a very high realm, there are yet several realms above the Brahma realm that are accessible through meditation. According to the Buddha, those in Brahma realms are also subject to rebirth.
 
Mahayana Buddhism, however, takes a different world view. This sect reveres several Hindu gods and divinities as holding an important place in the rites and rituals. These deities include major Devatas such as Brahma, Indra, Saraswati, Surya, Vayu, Varuna, Prithvi and so on.

• Of these 31 planes, the Arupa-Loka or the Formless Realm includes 4 planes. Here, beings are born as a result of attaining the formless meditation. Beings residing in these realms are possessed entirely of mind and have no physical form or location. Also, they are unable to hear Dhamma teachings. They achieve this by attaining far advanced meditational levels in another life. Since they have no connection with the material world, they do not interact with the rest of the universe.
• The Rupa-Loka or the fine material world is made up of 16 planes. Beings take rebirth into these planes as a result of attaining the jhanas. They have bodies made of fine matter. The devas of the Rupadhatu have physical forms, but are sexless and passionless. They live in several types of devalokas that exist in layers, far above the earth. These residents can be divided into 5 further groups, who exist at various levels of samsara. Out of these, the "non-returners" are the ones who will go on to guard and protect Buddhism on earth, and will pass into enlightenment as Arhats when they pass away from the Suddhavasa worlds.
• The next is the Kamma-Loka. Birth into these heavenly planes takes place through wholesome kamma. These devas enjoy all the good aspects of samsara, including aesthetic pleasures, long life, beauty, and supernatural powers. The heavenly planes are not reserved only for good Buddhists. These devas can help people by inclining their minds to wholesome acts, and people can help the devas by inviting them to rejoice in their meritorious deeds. It is important to note here that the Devas in these realms have physical forms similar to, but larger than, those of humans. They are also more interested in and involved with the world below than any of the higher devas, and sometimes intervene with advice and counsel. Due to not having direct knowledge of the realms above the Brahma realm, some of the Brahmas have become proud, imagining themselves as the highest creators of their own worlds and of all the worlds below them.

Religious Practices

The Samannaphala Sutta in the Digha Nikaya of the Pali Canon explains in detail the actual Buddhist concept of the true spiritual path. This treatise lists the various practices that the Buddha taught disciples as well as practices he did not encourage. Rather than stating what the new faith was, the text emphasized what the new faith was not.

Common religious traditions prevalent then and practiced by the non-Buddhists were negated and generally laughed upon. Strangely enough, though, the early Buddhist texts also exhibit a type of anxiety at having to compete in religiously plural societies.

Meditation - Combining Dhyana and Sila

According to the Maha-Saccaka Sutta, the Buddha recalled a meditative state that he entered by chance, during his childhood. Thence, he abandoned all the ascetic practices he has been performing so far and went in search of the true path of awakening. After finding what he was looking for, the Buddha could overcome all the obstacles in his path and truly attain enlightenment. Each time the Buddha encountered obstacles that caused the inner light to disappear, he automatically also found his way out of them. Finally, he was able to fully penetrate the light and entered jhana.

According to the early scriptures, the Buddha learned the two formless attainment techniques from two of his teachers, Alara Kalama and Uddaka Ramaputta. Some experts believe that these teachers belonged to the Brahmanical tradition. However, the Buddha soon realized that neither "Dimension of Nothingness" nor "Dimension of Neither Perception nor Non-Perception" lead to Nirvana. So he left them and continued on the path towards enlightenment.

Soon, the Buddha himself discovered an attainment beyond the dimension of neither perception nor non-perception, a stage he referred to as the "cessation of feelings and perceptions". Though the "Dimension of Nothingness" and the "Dimension of Neither Perception nor Non-Perception" are included in the list of nine Jhanas taught by the Buddha, they are not included in the Noble Eightfold Path. The Noble Path number eight is "Samma Samadhi" or Right Concentration. It is only the first four Jhanas which are considered "Right Concentration".

The Buddha taught that there should be meditative absorption, but that it should also be combined with a liberating cognition. The meditation or dhyana must be coupled with the perfection of Sila or ethics, in order for it to culminate in enlightenment. Some of the Buddha's meditative techniques were shared with other traditions of his day, but his idea of correlating dhyana to Sila was new and hitherto unknown.

Yoga in Hinduism and Buddhism

The concept and practice of Yoga is vital to both Buddhism and Hinduism. However, there are clear differences in the usage of the terminology in the two religions.
In Hinduism, the term "Yoga" usually implies the eight limbs of yoga as defined in the Yoga Sutras of Patanjali. Hindus believe that this was given to man with the idea that his individual soul or atman should bind or "yoke" with the Supreme Brahman.

According to Vajrayana Buddhism of Tibet, however, the term "Yoga" is used to describe any type of spiritual practice undertaken. This could include any of the various types of tantras like Charyoga or Kriyayoga, Guru Yoga and so on. In fact, some scholars believe that Patanjali was influenced by the success of the Buddhist monastic system to formulate his own so-called version of Yoga.

The terminologies used to describe various meditative states in Hinduism and Buddhism are quite similar too. The two most common terms here are Dhyana and Samadhi. These describe the stages of meditative absorption in both religions. Most notable in this context is the relationship between the system of four Buddhist dhyana states and the samprajnata samadhi states of Classical Yoga.

Aspect of Conversion

By and large, Hinduism as a culture has entirely stayed away from the concept of religious conversion. While it welcomes one and all with open arms, encouraging everyone to study its many intricacies, it does not actively encourage people to move over to this form of tradition and culture. While there are some who believe that in order to become a Hindu, one has to be born a Hindu; most others who see this philosophy as a way of life believe that one can become a Hindu by just adopting Hindu beliefs and traditions into one's life. Even the Supreme Court of India has taken the latter perspective on Hinduism.
 
Quite contrarily, Buddhism spread throughout Asia via evangelism and conversion. Even Buddhist scriptures depict conversions in the form of lay followers declaring their support for the Buddha and his teachings, or via ordination as a Buddhist monk. A person who "takes refuge" in Buddha, Dharma and Sangha is the one that becomes a Buddhist. Some sects of Buddhism stipulate the observance of formal conversion rituals. However, no specific ethnicity has yet been typically associated to Buddhism.

The Brahman and the Brahmin

The ancient Upanishads consider the Brahman or the Atman as the Supreme God, the One that Rules the World. The early Upanishads ascribe these characteristics to Lord Brahma. He is filled with light and he is invisible, unknowable, and also is omnipresent, omniscient and omnipotent. Both Brahma and the Brahman possess all these characteristics, and hence, they are one and the same, according to Hinduism.

The Buddhist concept of Brahman is quite different. According to the Buddhist texts, there are many Brahmas. These entities are actually a class of superhuman beings. They can be born again into the realm of Brahmas by pursuing Buddhist practices in their current lifetimes.

In the Pali Canon, Brahmins who appear in the Tevijja-Suttanta of the Digha Nikaya regard "union with Brahma" as liberation. Their main goal in this lifetime is to achieve that state, which ultimately leads them to nirvana. Buddhists believe this to be the right path, the path to the truth.

The early Upanishads frequently expound "association with Brahma", and "that which we do not know and do not see". The Pali scriptures, however, consider this as a "pernicious view", that ultimately causes more damage to the seeker.

The Buddha redefined the word "Brahmin" so as to become a synonym for "Arahant", replacing a distinction based on birth with one based on spiritual attainment. The Buddha explains his use of the word "Brahmin" in many places. According to his teachings, no one is an outcast by birth and no one is born a Brahmin. It is his deeds that actually decide whether or not he becomes a Brahmin. Only one who is totally pure of mind can hope to become an arahant, according to the Buddha.

The Concept of Non-Duality

Therefore, while the Upanishads focus on the static Self, the Buddhist view is more dynamic and believes that it is in the seeker's hands to make things happen. While the Brahminical view of the realization of non-duality is that it is a permanent state, Buddhism believes that it is a mere meditative state and does not offer a permanent solution to material suffering during the ongoing cycle of birth and death. The Buddha further averred that states of consciousness are the result of the yogi's training and techniques, and therefore no state of consciousness could be this eternal Self. 

The Buddhist idea of the liberated person and the goal of early Brahminic yoga can both be characterized as nondual, but in a different sense. The nondual goal in early Brahminism was to merge with the Supreme after death. For the Buddha, however, such propositions are not even applicable to the liberated person, as the truly liberated one is free of these types of concepts and intellectual reasoning.

Attaining Nirvana or Liberation

Interestingly, though the term "Nirvana" was very much in existence before the Buddha, it cannot be found in the early pre-Buddhist Upanishads. It was first used in Buddhism and can also be found in Jainism. This term was however used in the Bhagavad Gita - it is likely that Hinduism had been influenced by Buddhist thought that early in the day.

The terms, "Nirvana", "Vimokha", "Vimutti", "Mokkha" and "Moksha" are used often in orthodox Buddhist scriptures, to mean "Liberation".

Early Buddhism and the Upanishads

Early Buddhist literature does not make any mention of the Upanishads, which are part of ancient Hinduism. This is in spite of the fact that the earliest Upanishads had been completed before the emergence of the Buddha. Hence, it is likely that early Buddhists had considered the Upanishads as a part of the Vedas and had not thought of them as having special, mentionable significance.

The Buddhist texts, though, do describe the existence of mendicant Brahmins who spent their time wandering from place to place, in order to promote the value of the Upanishads.

Branches of Buddhist Philosophy

Since we are continuing our study on Hinduism vs. Buddhism, it would only be appropriate to also include the most notable branches of Buddhist philosophy.

Tibetan Buddhism

Buddhism from regions such as China, Kashmir, Japan entered the Himalaya and integrated itself with the schools of Tibetan Buddhism, which later went on to emerge as major branch of Buddhist philosophical thought. Yoga is the main aspect of Tibetan Buddhism.

• According to the Nyingma school of thought, many practitioners start with Maha Yoga and progress to higher levels such as Anuyoga and ultimately, the highest Atiyoga. Usually, the majority of practitioners stay within one yana for their entire lifetime.
• According to the Sarma tradition, the Anuttara yoga class is equivalent to the three most subtle yana of the Nyingmapa.
• Other tantra yoga practices include a system of 108 bodily postures, combined with Pranayama or breathing techniques. This is known as Trul Khor, or the union of Surya-Chandra nadis (the moon and sun prajna energies). Incidentally, the body postures of ancient Tibetan yoga are depicted on the walls of the Dalai Lama's summer temple of Lukhang.
• During the 13th and the 14th centuries, the Sarma tradition developed a fourfold classification system for its Tantric texts, which was based on the types of practices each contained, also giving importance to their relative emphasis on external ritual or internal yoga.

Zen Buddhism

Zen is a type of Mahayana Buddhism. This particular school of Buddhism is noted for its proximity with Yoga. Zen Buddhism traces some of its roots to yogic practices. Also, certain essential elements of Yoga are important both for Buddhism in general and for Zen in particular.

The Concept of Buddha in Hinduism and Buddhism

The Buddha to Hindus

There is much mention of the Buddha in many Puranas. Herein, he is described as an incarnation of Sri Mahavishnu, who manifested in order to delude either demons or mankind away from the Vedic dharma.
 
According to the Bhavishya Purana, during the Kali Yug, Lord Vishnu manifested as Gautama, the Shakyamuni. He continued to propagate Buddhism to people for a period of ten years. At the very first stage of the Kali Yug, the Vedas took a backseat and Buddhism came to the fore, with all men becoming Buddhists. During the course of this time, those who sought refuge with Vishnu would be deluded.

Considering this view, some scholars believe that the Buddha avatar, may have represented an attempt by Brahmin orthodoxy to slander the Buddhists by identifying them with the demons.

The Buddha to Buddhists

According to the biography of the Buddha, though, he was a Mahapurusha, originally hailing from the Tushita Heaven. He took birth on earth as Gautama Buddha. Before leaving his Tushita realm, the Buddha asked Maitreya to take his place there. There is no return or rebirth for the Buddha and Maitreya would manifest as the next Buddha on earth.

According to Buddhist scriptures, Krishna was a past life of Sariputra, who was the main disciple of the Buddha. Since he had not attained complete enlightenment during his lifetime as Krishna, he had to come back again and be reborn as Buddha's disciple, who attained the initial stage of Enlightenment with his teacher's grace. After he became ordained in the Buddha's sangha, Sariputra reached full Arahantship or attained total Awakening.