The inner guru is the awakening of the guru's force in the life, body and personality of the disciple. It is the flowering of the guru's energy which is manifesting inside. The word 'guru' means dispeller of darkness. It can be a person, it can also be a concept or a thought, it can be anything. The inner guru is something which helps you to overcome the limiting traits of your nature, and to have a broader vision concerning yourself and the cosmos.
For many people guru is a book, and for many guru is a living presence or an idea of faith and devotion. For the Sikhs the ultimate guru is the Guru Granth Sahib. The main text and guru which they follow with the utmost reverence and faith is a compilation of the teachings of the ten gurus of their tradition. They do not have a physical, living guru. Even the followers of the Sanatan spiritual tradition in this region have the Vedas and the Upanishads for their guru.
For many spiritual aspirants gurus are living persons or forces, while for others guru is an idea or a concept of divinity towards which they have deep inner reverence, respect and faith. So the concept of guru can change. However, whatever form of guru you have is simply a means or a medium through which you can overcome your limitations, remove the veil of ignorance and experience light.
It has been a human trait since the beginning of creation for man to relate himself to someone manifest. We have always looked to another person to guide us in our process of discovery. Therefore, in the modern context, guru means a relationship with a living person who represents the culmination of an idea or the fulfilment of a concept. This fulfilment of a concept also becomes a very important drive. People who are bhakti oriented find solace when they go, for example, to the Hare Krishna community. People who are intellectually inclined felt satisfaction when they visited somebody like Swami Chinmayananda, who was a highly intellectual person. People of all odd shapes, colours and sizes like us feel attracted towards a person like Swami Satyananda.
Now, in order to experience the inner guru, the disciple or aspirant has to make some effort to let down his defences and allow the force of the guru to transform his entire being from inside. If you want to take a bath then you have to take off your clothes first. If you have a job to do then you have to adopt the method necessary to do it. If you want to experience the inner guru you have to surrender.
You have to surrender because as long as there is the barrier of I am a distinct person from the guru and I am the judge of my guru's instructions, then you may desire in the deepest core of your being to experience the inner guru, but you will not experience it because there is duality, dvaita bhava. There is the notion of 'I' and 'he', there is the notion of 'me' and the guru as separate beings.
The two words 'but' and 'and' do not exist in surrender. 'But' represents the ego, 'and' represents one's ambition. If you surrender then you will experience the inner guru. For that you need to be a different person. You cannot be yourself, you cannot be what you perceive of as being yourself. Not I am this person having this idea, this drive, this motivation, this desire, this feeling. If that is what you are then it is not really worthwhile or necessary for you to become a disciple.
If you do not consider yourself as I am this, I am that, then it is easier to merge with the wider body of the guru's energy. It allows for more freedom. Otherwise it is like trying to swim across the river carrying different packs on your back which are pulling you down. The person on the other side says, Throw off the burden from your back! and you say, But it has all my life experiences in it. How can I do that? So if you can't do it, sink. Who cares?
The guru is not going to care, he has to care for everyone. Why should he kill himself because of the whims of one who does not wish to listen to him. That is the practicality of being a guru. The disciple has to be of a different type, one who can simply say, Okay, all my burdens are off, I have created freedom of movement. Now what do I do?
Ganga Darshan, 1994