Yoga stands for union between the lower and the higher mind, union between the lower and the higher self. The practices of yoga will get you there. When you take an aspirin you have the side effect of peptic ulcer. The side effects of yoga are positive; they give clarity of mind, a good personality and good values. But they are side effects. The aim of yoga is union and to achieve union, shuddhi or purification is emphasized. According to yoga, purification takes place first at the level of the body, and then at the level of the pranas to allow a free flow to each and every part of the body. Purification at the mental level balances and directs the mental energies.
Yoga speaks of three bodies: the gross body, sthoola sharira, the subtle body, sukshma sharira, and the causal body, karana sharira. Purification takes place in all three dimensions.
Everybody knows how to clean their body and some of you know how to clean your mind by doing the practices of antar mouna, ajapa japa or meditation. The body and mind relate to the gross and the subtle body.
However, you do not know how to reach and purify the causal body. That is the most important purification, because all your karmas, samskaras, vasanas, desires and impressions are stored there. The impressions of many incarnations, from the amoeba to the human being are stored in the causal body.
These impressions rise to the surface from time to time in the form of thoughts and dreams. They trouble you and you don't know how to handle them. You have to purify those impressions because without purification you cannot progress. In life there are always obstacles; they stand in front of you in the form of agony, pain, depression, greed and hatred. According to yoga only sound can reach the causal body and influence this dimension of your being.
Samkhya and yoga say that the whole universe, the whole creation, the solar system, the galaxies, the mountains, rivers, plants, trees, animals, you and me, are all evolutes. We have all evolved from sound, we are products of sound. If this is true, then sound will definitely affect us in a positive way because that is the source from where we have evolved. Today, science says that this whole creation is a play of sound and light, therefore agreeing with the system of Samkhya.
There are three principles in Samkhya: bindu, the nucleus, nada or sound and kala or time. In the nucleus, there is a vibration, bindu spandana. From spandana or vibration emerges the sound, nada, or the transcendental sound which has been defined as Om. If you have read the Bible you will know that the first line is: "In the beginning there was the word, and the word rested with God." In yoga, in tantra and in Samkhya they called that word Om. All the sounds have evolved from that one sound, whether it is the tick of your watch, the words you speak or the music you hear.
Sound has two qualities: one is volume and the other is frequency. Mantras have a very high frequency and exist all around us. We have to refine and tune the instrument so that we can receive them, in the way the rishis and munis did. They refined their instrument so perfectly that they could receive and realize these mantras. They became the seers of the mantras and handed them down to us to utilize for our own benefit.
Sound has a very great influence which we can experience in our daily life. If we want to relax, we listen to nice music, and at once we are influenced. If I say the word chocolate, immediately the salivary glands will become active in those of you who like chocolate. If I tell you that you are a nice person, immediately you will start feeling nice. If I tell you that you are a rascal, immediately your mood will change. That is the effect of sound on a gross level. We know that sound can produce an avalanche, it can shatter glass and influence plants, trees and animals. If we play music to our plants, they grow better. If we play music to our cows, they give more milk.
Mantra is sound of a very high frequency. When it enters our consciousness, it penetrates deep and begins to act on the causal body. Mantra is a strong detergent which we use to bring samskaras and vasanas to the surface. Once at the surface, the impressions are purified. Mantra, along with asana and pranayama, is important in yogic science. Therefore, it is vital to introduce mantra into our practice and life.
Three-quarters of our brain is not functioning. These are the silent areas of the brain which have to be activated. If we want to realize our full potential, a mantra is necessary. There are general mantras like the Mahamrityunjaya and Gayatri mantras, and the mantra Om which is a universal mantra. However, the mantra which will accelerate our evolution is the guru mantra.
With a mantra we have our greatest treasure which will help us in life. It acts as a kavacha, a protective shield which does not allow the negative and destructive influences to touch or harm us.
The ritual of mantra diksha conveys an impulse from the guru to the person who is receiving the mantra. Diksha is a word derived from the root dik, which means direction. The energy which we awaken through the practices of yoga has to receive a direction, otherwise it dissipates. We have to direct the energy to higher centres, and mantra gives direction to that energy.
The sound from which we have evolved is energy. It is entrapped in the matter of the body and it has to be liberated. If we want to have higher experiences and achieve union between the lower and higher mind, union between the lower and higher self, then we first have to liberate energy. Mantra is one of the tools to liberate energy.