Answer
Hinduism is a complicated religion with multiple gods who may or may not all be just avatars (representatives) of the tasks performed by a single supreme lord. Different sects within Hinduism emphasize the worship of different gods based on proclivity, leading, and needs; and different Hindu teachers interpret the same writings with different meanings. The supreme lord in Hinduism also represents the supreme truth of the cosmos.
Three of these Hindu gods are sometimes combined to make up the “Trimurti,” a triad of gods (usually Brahma, Vishnu, and Shiva). The word Trimurti comes from the prefix for “three,” tri-, and the Hindi word for “image” or “representation,” murti. Their specific tasks (Brahma creates, Vishnu maintains, and Shiva destroys) keep the world in a state of equilibrium. Vishnu and Shiva are two significant avatars or representations of the supreme lord, and that supreme lord has three aspects, according to the Rigveda (1700–1100 BC). The Maitri Upanishad (800–400 BC) has a note, not original to the text, about the combination of Brahma, Vishnu, and Shiva. The first mention of the Trimurti itself, however, was in the poem “Birth of the War God,” written in the 4th or 5th century AD. It wasn’t until the Puranas (AD 300) that the members of the Trimurti were brought together to receive their defined roles in the caring for the cosmos.
Brahma creates and gives life force to his creation. One of his main aspects is knowledge and the dissemination of knowledge. He is barely worshiped as an individual today and has only a handful of temples in India; he was caught in a sin (being too lenient and blessing demons, trying to seduce his daughter, or lying, depending on the story) and has to work under the supervision of Vishnu or Shiva. Brahma the god is not to be confused with Brahman, meaning “absolute, supreme reality or the manifestation thereof,” or Brahmin, which is the Hindu caste of priests.
Vishnu maintains the worlds in his care. He was a minor god in the early days of Hinduism, and even now some of his incarnations, such as Lord Rama and Lord Krishna, are worshiped more than he himself. Hindus claim that Buddha is another incarnation, but Buddhists, who believe in enlightened humans instead of gods, disagree. Vishnu represents kingship and military power and enforces order with physical force.
Shiva (or Rudra-Siva) is the destroyer or absorber god. He and Vishnu often competed for the title of “Supreme Lord.” Shiva is prone to fits of anger, and his destructive bent comes from his desire to see the world newer and purer. Like Vishnu, his incarnations are worshiped more than he is. He is the god of male fertility but also of asceticism, as self-denial supposedly increases one’s “ascetic heat” and makes one more attractive to women.
The Hindu Trimurti is the representation of the supreme lord’s work to control the cosmos as illustrated in the combination of the three gods in these specific roles. Each of the three gods has different interests, but when their powers combine to focus on creation, maintenance, and destruction, that is the Trimurti. One theory is that the concept of the Trimurti came about in order to bring worshipers from different Hindu sects into a more cohesive group. Vaishnavites who worshiped Vishnu and Saivites who concentrated on Shiva could join in worshiping a single supreme lord who had the aspects of a maintainer and destroyer, with the addition of a creator, while still concentrating on their particular sect. In reality, those who specifically worship Vishnu or Shiva are just as likely to either ignore the Trimurti or explain how their favorite god is the supreme lord who created the other two. Other Hindu sects combine different gods into “Trimurti,” including Brahma, Vishnu, and Bhava, or replace Brahma, Shiva, and Krishna. At any rate, the Trimurti, while mentioned in Hindu literature, isn’t a significant part of Hinduism as practiced but more of an explanation of the workings of the cosmos.
The defined concept of the Trimurti is a relatively new addition to Hinduism, but the importance of the number 3 is not. Hinduism teaches three layers of nature, three states of being, three divisions of both time and the day, and three phases of life and self-realization, to name a few. It flows naturally that the supreme lord would order the cosmos via characteristics from three of his avatars.
The teaching of the Trimurti as three manifestations of the supreme lord is similar to the heretical Christian teaching called Sabellianism. In Sabellianism, the Members of the Trinity are not individuals but merely three different representations or forms that God chooses to present Himself as. The Trimurti is also referred to as the Hindu triumvirate, a governing body made of three individuals, which is the opposite idea of Sabellianism as the members’ identities are primarily that of individuals who work together.
The Hindu Trimurti is not like the Christian Trinity. The Trinity is one God in three co-equal, co-eternal Persons. Many Hindus reject the concept of the Trimurti, and even those who accept the Trimurti see the triad as three Hindu gods appearing as avatars, manifestations, or modes of the supreme lord; they are not separate persons.