Sanskrit language is considered to be a divine language of great potency. The fifty letters of the Sanskrit alphabet are called Matrikas (mothers) since they together constitute the source of all ancient sacred wisdom. Each syllable, when it ends with Anusvar (spelling ‘m' at the end), becomes a mystic syllable. Each part of the human body is assigned with a different mystic syllable. When a mystic syllable is uttered while touching the assigned part of the body with the hand, benefic vibrations spread to that part. Thus the magical property inherent in the sound of each mystic syllable can be derived to produce good effects on human life.

When the syllables combine to formulate cryptic words or sacred formulae they become Mantras . All Mantras have esoteric meanings and special astral potencies, which remain beyond the comprehension of ordinary persons. Thus the Mantras are mysterious sounds containing the concentrated power of the sacred words or formulae, directly revealed to the ancient Rishis (sages) through the direct inspiration of the Divine during the highest phase of meditation. Such Mantras constitute the main body of the Vedas. Apart from such directly revealed Mantras , the ancient sages composed many powerful Mantras after long meditations. These composed Mantras , too, carry profound significance in many ways. Some are used for rituals, some for protection or as an armor ( Kavach ), some for destroying evil beings, some for enlightenment and wisdom, some for bringing mystical experience like trance, and some for invoking the personal deity.

A branch of learning devoted exclusively to the study of the Mantras , is called Mantra yoga consisting of sixteen stages. This forms the basis of mostly all the varieties of yoga disciplines such as Karma yoga, Jnana yoga, Bhakti yoga, Nada yoga, Hatha yoga, Raja yoga, etc. Many Siddhis (miraculous powers) also accrue from the mastery of Mantras . As a matter of fact, there is nothing which remains beyond the power of the Mantras .

A Mantra derived from a book is of no practical value. Simply uttering a Mantra read from a book is merely waste of time and energy. It will not yield any result. In all the paths of spiritual practice, it is recommended that the Mantra should be acquired through the voice of a realized master (Guru). Only such Mantra carries mystic power and its repetition ( Japa ) proves fruitful. Receiving a Mantra from the mouth of a Guru is known as Mantra Diksha (initiation). When a disciple hears a sacred Mantra intoned by the Guru and understands its intelligible meaning through the words of the Guru, he is considered to be properly initiated. Mantra Diksha is generally the first initiation given by the Guru to a disciple, who subsequently enters into the fellowship of that particular spiritual tradition. A Mantra should not be transmitted to another person by anyone except the Guru who has mastered that Mantra . Gaining mastery over a Mantra involves the revealing of its esoteric meaning ( Mantrartha ) during meditation, the awakening of its inner energy ( Mantra Chaitanya ) and the manifestation of Yoni Mudra . The esoteric meaning of a Mantra does not belong to the rational language serving to communicate ordinary experiences. The awakening of a Mantra is a spontaneous energetic experience unfolding the unlimited potency of it. During such awakening an aspirant stretches the whole body, experiences exhilaration and heart stirring affection, sheds tears of joy and utters Mantra interrupted by sobbings. The final technique of mastering a Mantra is difficult. It involves a secret yogic exercise called Yoni Mudra , which is a technique of mystical physiology. It is a profound mystical experience manifesting at an advanced stage in yoga. Summing this up, in Kularnav Tantra it is said: “A Mantra is not mastered even after repeating it a billion times by a person who does not know the esoteric meaning of it, has not experienced its awakening and knows not the Yoni Mudra ”. This shows that Mantra and yoga are inseparable and the former constitutes an integral part of the latter. Elucidating this, in Rudrayamal Tantra it is said: “There is no Mantra without yoga and there is no yoga without Mantra . The ultimate reality (Brahm) can be attained only through the practice of both”. Thus the Mantra initiation is of great importance for all spiritual aspirants.