The guru is someone who has walked the path and so has a complete understanding of what you are approaching.
The essence of creation, that which is manifest and also that which is not manifest, lies in stillness. Just like all lights combine to form white light, similarly, a combination of various aspects of creation — all the sounds, colours, textures, tastes and fragrances, in totality, is stillness. Creation emerged from stillness and the journey back to the source, to reality, cannot be carved till the time one is still. To see a coin at the bed of a water bowl, one needs to still the water off all ripples. Similarly, to see reality, one needs to still oneself off all desires and thoughts.
How does one achieve stillness? The answer lies in the science of dhwani, or mantras. Vedic masters gave us three powerful mantras of Shivohum (I am Shiv), Tat Tvam Asi (That is You) and Aham Brahmasmi (I am Brahm) which hold the shakti to take one back to the source, to stillness. But then, repeating these words alone would not give you the experience of stillness, these shaktis need to be channelised inside you and this is the role of the guru.
Various cultures of the world concur that there is one supreme reality. But then no enterprise can be a one-man show — in a company there is a CEO, and also managers, technicians and labour and guards and so on. So how could all of creation be run by one alone? The vedic masters gave us the answer: “Ekohum Bahusyam” (I am one; let me become many). Hence, the various forms of gods and goddesses, where each is assigned a specific task or role. And one has to go through all these energies to reach the finality, or reality. These may be seen as locks on various gates in the journey, the key to which is possessed by the guru in the form of mantras or dhwanis. Ganpati, for example, is the guardian of the first gate, the entry.
The guru is someone who has walked the path and so has a complete understanding of what you are approaching. For example, Surya dev was brought to prithvilok by Bhrigu rishi and so rishi Vishvamitra could not have reached the gayatri without invoking the shakti of his guru, rishi Bhrigu. Hence, “bhargo devasya dheemahi…” The guru gave him the key to Surya. Similarly, at various stages of sadhna, the guru gives the key to a sadhak to open various locks or doorways.
There are essentially six locks in the journey of the spirit, namely, those of food and shelter, sexual gratification, power and status, love and creativity. A layperson has awakening till only the first three levels, and doesn’t desire for anything beyond, he/she continues to do the same things over and over again as there is no desire or awakening of higher centres.
Here it is important to understand that one cannot continue doing the same things endlessly as nothing in creation is constant — it either moves up or down. And if one is not going up, then he/she is definitely going down… to lower dimensions. The only way to reverse the journey is to find a guru and to earn his/her grace by forwarding the guru karya. The guru is always given a karya or task which he has to perform towards creation, without completing which he/she cannot go further. If you become instrumental in forwarding this karya, you earn his/her grace and unlock the first dimension. Then the guru gives you the mantra and gradually you move to the next.
These days the guru is normally confused due to big buildings, hospitals, dance and music. On the contrary, Vedic shastras prescribe stillness, vairagya and mantra uccharan as traits of the guru only.