A mantra (from Sanskrit: man- "to think" and -tra meaning, tool) literally means "instrument of thought." Originating in ancient India out of Vedic Hinduism, mantras serve a variety of functions and are especially popular as aids to meditation and devotion. As powerful sound vibrations, mantras encompass various forms of sacred utterance (syllable, scriptural verse, or sacred formula), which can be repeated silently or chanted for different purposes such as instilling concentration, facilitating spiritual growth, and helping to visualize a deity. It is said that a mantra, when recited with proper understanding and intonation, can revitalize the mind with mystic power and help deliver it from illusion to enlightenment. Mantras have also been used in religious ceremonies to accumulate wealth, avoid danger, or even allegedly to eliminate foes.
Different sounds have different effects on human psyche. If a soft sound of wind rustling through leaves soothes our nerves, the musical note of running stream enchants our heart, thunders may cause awe and fear.
The sacred utterances or chanting of Sanskrit Mantras provide us with the power to attain our goals and lift ourselves from the ordinary to the higher level of consciousness. They give us the power to cure diseases; ward off evils; gain wealth; acquire supernatural powers; worship a deity for exalted communion and for attaining blissful state and attain liberation.
Over time, the most famous of all Hindu mantras became Aum, which is called the "pranava mantra" (the source of all mantras). Aum is considered to be the most fundamental and powerful mantra, and thus is prefixed and suffixed to all Hindu prayers. It represents the underlying unity of reality, called Brahman, the godhead, as well as the whole of creation. Merely pronouncing this syllable is said to allow one to experience the divine in a very direct way.
One of the main forms of puja, or worship, in Hinduism is repetition of mantras (called Mantra japna), which is said to lead to moksha/liberation. Essentially, Mantra Japa means repetition of mantra, and has become an established practice of all Hindu streams, from the various Yoga to Tantra. It involves repetition of a mantra over and over again, usually in cycles of auspicious numbers (in multiples of three), the most popular being 108. For this reason, Hindu malas (bead necklaces) developed, containing 108 beads and a head "meru" bead. The devotee performing japa using his/her fingers counts each bead as he/she repeats the chosen mantra. Having reached 108 repetitions, if he/she wishes to continue another cycle of mantras, the devotee must turn the mala around without crossing the "meru" bead and repeat.
Any shloka (scriptural verse) from holy Hindu texts like the Vedas, Upanishads, Bhagavad Gita, Yoga Sutra, even the Mahabharata, Ramayana, Durga saptashati or Chandi are considered powerful enough to be repeated to great effect, and have therefore the status of a mantraIn addition to Hinduism, mantas are also used by Buddhists, Jains, Tantrikas, Sikhs and followers of some new religious movements. The practice of prayer in the Abrahamic religions is said in some ways to have a similar function to mantras.