This page describes some ideas, themes, and beliefs which are common to a number of different religions. Some beliefs have passed directly from one religion to another, but in many cases the same idea has arisen independently in different religions.

The basic idea of reincarnation is that an organism's soul leaves its body at death and then enters the body of another newly-born life form. Thus over time it passes through a series of successive existences in different physical bodies. According to an associated idea called karma, actions in one life will affect the form of existence in the next life. In particular, through good behavior a soul may be able to pass to higher and higher life forms in successive stages of existence.

Belief in reincarnation is found in a number of religions, including Hinduism, Buddhism, Jainism, Sikhism, Manichaeism, and Gnosticism. Adherents of some of these religions also believe that an individual can permanently escape the cycle of birth and rebirth by reaching a state of enlightenment or nirvana. In Tibetan Buddhism, the Dalai Lama is always the reincarnation of his predecessor.

Gods in Human Form
The idea that a god or goddess can appear on earth in human form is a theme found in many religions. Such a belief was especially common in the ancient polytheistic religions of the middle eastern and Mediterranean religions. For example, in the epic works of the Greek author Homer, gods and goddesses often appear in human form in order to intervene in events taking place on the earth.

In Hinduism, a manifestation of a god in human or animal form is known as an Avatar. The most important of these Avatars are manifestations of the God Vishnu, and have appeared at critical points in history in order to protect the world from an especially evil threat. See avatars for more about the history of these interventions.

Founders of several major religions have been viewed as incarnations of a god. These include Zoroaster, Jesus, and the Buddha Gautama.

Sacred Texts
Sacred texts or scriptures are an important part of many religions. Many of these writings are thought to have come directly from a god or goddess, usually as some kind of miraculous revelation. Others are known to be compositions of an original founder of the religion, or early leaders or prophets, but are now considered to be divinely-inspired.

The sacred writings of Hinduism include the Vedas and the Upanishads. The Hebrew Bible, the sacred text of Judaism, was created over a period of at least eight centuries, but no new books have been added in two thousand years. Most Christians also consider the Hebrew Bible to be a sacred text, but have added some additional books to it in the form of the gospels and other books of the New Testament. Followers of Islam believe that their sacred book, the Quran (or Koran), are the words of Allah given to Mohammed through the voice of the angel Gabriel.

Adherents of most religions consider it very important to preserve their sacred writings exactly in their original form.

Spirit World
Spirits are invisible supernatural beings, such as ghosts and demons, that sometimes interact with human beings. Some spirits are helpful to humans, or at least benign, but most are evil and harmful. Usually they are considered to be less powerful than true gods.

In Christianity, the Devil is served by evil spirits called demons. Originally these were angels, but they were turned into demons after they assisted Satan in his revolt against God. Some Christians believe that a demon can get inside a person's body and gain control of it. This is called demonic possession, and it produces behavior that resembles mental illness. According to the gospels, Jesus had the power to expel a demon from a victim simply by ordering it to leave. Go to this demonic possession page for more information about this condition.

In some religions, ghosts are the spirits of dead people. They may haunt the former house of the dead person or linger in the cemetery where he or she is buried. The ghost of someone who is murdered may try to get revenge against the murderer. And if a man dies in a violent accident, his ghost may haunt the scene of the accident.

Body Mutilation
Perhaps the best known example of religious bodily mutilation is the Jewish act of circumcision, the removal of the foreskin of the penises of infant males. This ancient practice was also adopted by some Christian groups, and both Jews and Christians continue to perform it.

Another old practice, tattooing, has also been used for religious purposes. Followers of some ancient Greek and Roman pagan religions used tattoos to show their devotion to particular gods or goddesses.

Self-wounding and self-whipping are a feature of many religions. Some Christians have attempted to re-experience the sufferings of Jesus by giving themselves wounds or markings known as stigmata. Another form of stigmata is found in Islamic societies.

Ritual mutilation has been observed in primitive tribal groups throughout the world. In many cases it is done as part of an initiation rite.

In many belief systems, a person's soul (or consciousness) continues to survive after the physical body dies. This continued existence is usually thought to take place in a spiritual realm, or possibly a different universe or dimension. This differs from reincarnation, since the individual isn't reborn in a new body.

Many religions have ideas about the places that these souls go to. Often there are at least two possible places, and which one the soul enters is determined by the kind of life that the person led. In Christianity, for example, the souls of saved people go to heaven, whereas the souls of the damned go to hell. However in a few religions everyone's soul goes to the same place.

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