A mantra is expressed in human language and developed by human consciousness. A mantra can exist in any language. What is essential though is that it goes through the human brain, human consciousness the human mind.
A mantra is not sound, but in fact the origin of sound. And sound originates from radiating energy. So we can say that radiating energy is the source of sound. Sound can create good or bad energy. Sound can create wars or stop wars. Sound can make you happy or unhappy. When someone tells you good things you are happy, and when someone shouts you are unhappy. It can be a blessing as well as a curse. The way in which you utilize and filter sound determines how it will influence prana.
Prana is maintaining our life. Maybe we can say that the atma (the Self) is prana (energy). You cannot see prana, you cannot measure it, and you cannot destroy it. Prana comes, prana goes. Prana is connected to something for a while. Prana is in the entire body. We cannot say where the soul is located within the body. It is in the whole body. We say that God is in every heart, because the heart is so sensitive, we feel everything there. Some do not believe this and ask, how could God 'sit' in the heart. If you go to a surgeon or cardiologist and ask if he has seen God in the heart while operating, or if there is any special vibration in the heart, he will say: "No, it is the same as all other organs. It is a pump, it weights 300g and when it stops, life is gone."
Some say that God is in the brain and this is also true. In fact, God, I, or the soul cannot be centred, because it is everywhere. That's why Self-realisation is a great problem for many people. Many people think, "When I get Self-realisation I will see my Self in my heart, and know: 'Yes, this is me. Now I can see it!'" But it is not like this. It is very hard to explain what Self-realisation is - what you realise and how you realise the Self. Self is not like the body, which you can see in a mirror or on a photo. How can you see the Self? Self is not like a picture or something that you can close away and say, "Now I have Self-realisation". It's not something that you can have. Self, prana, mantra and life you cannot describe. You can talk and talk, yet however hard you try, the Self is still something different. You cannot define it. It's like an onion: you take away all the layers, but still you cannot grasp the "onion".
Mantra is very closely connected to the Self, and prana is the radiance of being the Self. The way you think and speak sends out your prana, your energy, your blessings, and this has an effect on others. When you think or say something, you have already created a mantra and with that you give your prana. Blessings are good from everyone, even from your enemy or from a crazy person. And in the same way a curse is not good from anybody, even from God.
Your Guru-mantra has immense energy, because it is given from the Master with his blessing. When you repeat it with your whole being, you put even more energy into it, and that will purify you. When you meditate and repeat your mantra, in the field of your own phenomena - your existence which has come together from many, many lives - the mantra will detect and root out certain tendencies and karmas. It will make you aware of your problems. And so you should utilise your buddhi and viveka to calm down and finish these problems - without becoming angry and without getting scared. Therefore, when you practise mantra, many vrittis (thought waves) come, because the mantra brings up many things and purifies many things. It's like the sun rising - as it rises darkness disappears.
Say your mantra inwardly before you say anything, because it creates such positive energy that you can't become angry or jealous. Everything you say will have been filtered through the positive energy of the mantra. Holy Guruji always said: guru satsang, guru seva and mantra. Very often he said antahkarana suddhi - purification of the antahkarana [the mind, consciousness, intellect & ego] - that is the work of the mantra. Repeat, repeat, repeat, don't just count, repeat.
Take a sankalpa, do 5 malas every day, and the rest of the day repeat it as much as you can. Just repeat, don't count.
Mantra is a blessing, a self-blessing. You received mantra from the Master with his blessing, and the more you repeat it the more you bless yourself, and the more you bless the world. But don't go around and say "I bless you. I give you blessing". A great one does not speak about himself, saying how great he is, nor does he sing the glory of himself. A diamond never praises its own value, but we honour its value and admire its beauty.
The more wise you are, the more humble you become; the more spiritual you are, the kinder you will be.
Free yourself from the prison and don't imprison yourself again by thinking negatively and talking badly of others. Some are in the prison of their emotions and others are in the prison of bad thoughts. Everyone is caught within something. To be free from all this, that's called Saha Ant, moksha, freedom. Free yourself from that inner prison.