Swami Vivekananda spoke at length of mediation on Aum during bhakti-yoga, and of an even more extended meditation during raja-yoga. He explained that the pravana(mystic syllable) Aum represents all of the words and all that exists in the universe. We therefore move from the creation to the Creator, which is the path followed by devotees.
Mantras became more and more prevalent, most likely during the time of the Atharva-Veda, when they served as incantations aimed at obtaining success in worldly pursuits, victory, the destruction of enemies, possession, or the success of some magical acts. But during this period the science behind the mantra did not progress as much as in the tantras, where the mantra is an integral part of the homage paid to various deities. The tantric school is important in Hinduism, because it provided a form to the homage which is more or less similar throughout India. In addition, tantric philosophy is satisfying; tantric yoga is commonly practiced and, furthermore, all of the rites that are currently carried out are tantric.
If God is One and alone—Brahman, according to the Upanishads—then what do the different deities represent?
God is one, but he is worshipped in various forms, each of which represent different aspects of the divine. When thinking of the loving God, we meditate on Sri Krishan—this idea is deeply established in Hindu tradition. When we think of wisdom, we meditate on Sarasvati. For strength, we meditate on shakti. For success, on Ganesha. For prosperity, on Lakshmi. And for goodness, on Shiva.
Meditating on God-without-forms, whose nature is so diverse, eternal, and infinite, is not easy for everyone. Those who are not ascetics conserve a form of attraction that keeps them attached to this world. The mantra provides a lot of help for these people to meditate. During religious ceremonies, special drawings called yantras and images are used. The worship of images is said to be primitive, while the worship of yantras is perceived as being slightly more refined. However, what is preferable is meditation on the mantra, which is more effective.
For a fervent worshipper, and for a rishi, a mantra is divinity itself. On meditating on divinity, one arrives at illumination. Previously, the word rishiwas not used as often in India as it is now. Rishi is not a title, it is instead a very rare state of knowledge. For example, Ramana Maharshi is venerated throughout India as the only rishi of our time. A man cannot declare that he himself is a rishi. People recognize him as a sage who has realized the Supreme. A rishi has had a vision of the Supreme. He has seen the mantra.
The Vedas were not composed by a few people. They were directly revealed to rishis. It is a revelation. It is therefore said that those who transmitted the Vedas were rishis. They received the illumination while meditating on the divine. It is as a result of this that they understood the vast power of focused thought. This is the power of the mantra.
We cannot consider a mantra as a word or a syllable, because it comes from a revelation that is attained under specific mental states and is obtained following spiritual practice. Anyone can follow these same practices. By accomplishing them, he or she can attain the same spiritual level as that of the rishis or of a fervent worshipper. That person will then have the same revelation. I hope that you will understand this clearly.
We accept the mantra of a rishiwho received the illumination, who saw the mantra et who transmitted it to us. By accepting the mantra, we wish to follow the practice that our teacher transmits to us. Thus, little by little, our mind is elevated. When it arrives at the same spiritual level as the mind of the rishi who had the illumination, we will also have that same illumination. We will be in the presence of divinity. At that moment, it is said, the mantra becomes illuminating, which means that it is capable of transmitting illumination.
We can ask ourselves many questions when hearing about such a little-known subject. Above all, one must have the will to follow these practices and to experience them. The vibration of the sounds in a mantra appear to only be physical vibrations, in our ordinary language, which thus seems to have little importance. However, for the faithful and the convinced, the sounds of the mantra are the mantra itself, identified to the deity, and capable of giving the illumination. To reach this state, one must constantly practice the japa, whose goal is to transform the ordinary sounds of a mantra into a source of illumination.