The word 'guru' has been used, abused and misused in many ways. Today 'guru' simply means either a teacher or a master, but these definitions do not do the word justice. Guru means the dispeller of darkness and ignorance. It is a name denoting a quality of God.
Just as the manifest form of God is recognized either as an avatar, an incarnation or as a messenger or son of God, the unmanifest aspects of God are recognized by names denoting certain qualities: satyam, the truthful one, sundaram, the beautiful one, shantam, the peaceful one. Guru is one name for the transcendental nature of God, the dispeller of avidya, darkness and ignorance, and tamas, lethargy and stagnation. The use of the word 'guru' came about when certain people started to tell the divine, transcendental, spiritual truths to ordinary people in order to improve their quality of life. Since they were dispelling myths, doubts and ignorance, such people were also called by the name guru.
You should remember the guru not as a person in a physical body, but rather the energy that is flowing through the person. Just as the spirit in a child's body is eternal, similarly, the force of the guru in whom these energies are manifesting is eternal. The spirit does not change; the body evolves. A child becomes a young man, the young man becomes an adult, the adult becomes an old man, the old man dies. While the body is undergoing changes, decay, and ultimately death, the spirit that entered the womb remains the same.
The force of the guru is similar. It is the spiritual power inherent in every individual. When it awakens and becomes a beacon of inspiration, wisdom and light, then it is recognized as the shakti, the force of the guru. When it is dormant, not awakened, then we are what we are. This spiritual energy which manifests in a person's life and touches the lives of many other beings is the force that stays with the aspirant all the way through, even when the carrier of this force, the physical being, leaves the mortal frame. In this way, the association with the guru is eternal because it is an association with your own spiritual nature.
How can one develop a relationship with the guru? There are two ways. Firstly, if you think of and identify with the guru as a person, with a body, a mind, an image, a form, a name, then developing the relationship is emulating the life and teachings of the guru. Secondly, if you identify with the transcendental aspect of the guru, then again it is realization of the spiritual qualities and nature within you. Therefore, it is said that the guru is within. The external person becomes the catalyst to give the inner experience of guru.
If you have faith in the guru and adore, worship and love the guru, then that is an indication of your love for God as well. I do not see them as being different. In the transcendental form, the guru is God. In the manifest form, the guru is the spirit of God manifesting in a body.
Jesus was a guru in whom the light of God shone, so was Mohammed and all the other saints and sages, but when we speak of the transcendental nature of the guru, we are referring to the spiritual energy of God. God has different energies as well. The material energy of God is known as maya, as prakriti. The spiritual energy of God is known as guru. This is how one has to understand the concept of the word 'guru'.
—Ganga Darshan, December 17, 1999