Guru is one who teaches us something new which is not known to us. A teacher of primary school who started my ABC's with the invocation of Shri Ganeshay Namah (prostration to the Lord of intellect) made me capable of becoming a doctor. He did not leave me there only, but used to come to my home every year for his guru dakshina. So, basically he had all the contacts of guru and disciple with me.
The gurus who lift us externally are teachers and professors in schools and colleges. They enlighten us in worldly sciences and behaviour which enable us to conduct our external affairs. But a guru is also one who teaches us internally on many different levels of awareness, such as: devotional, scientific, therapeutic.
Previously, it was the tradition to have a guru from early childhood, and all the sons of royal families received their training in this way. So, when Arjuna was going to battle on the field of Kurukshetra, he requested his guru and friend, Lord Krishna, to accompany him. Such was the feeling for guru that, when one entered the samsaric Kurukshetra, he felt that naturally his guru must be with him. But now, this is no longer so.
What happened in Kurukshetra? Affected by the emotions. Arjuna went into a deep depression and threw down his weapons before Krishna, refusing to tight in the battlefield. We can easily understand the feeling of Arjuna when we become depressed in daily life and are unable to perform our daily duties. This creates conflict for ourselves, our families and society, as well as the nation.
So, Arjuna asks his guru:
"Whatever is most useful and best for me, please tell me, because I am in fear and do not know dharma at present." Gita, 2/7
A sick man requiring medicine will run away from the battlefield. Hence, Lord Krishna treated him, saying:
"Do not follow the religion of body, mind and intellect. Follow your own religion, because the religion of body, mind and intellect will give you fear. Only 'observe' the religion of body, mind and intellect and do your own duty. Consider all actions as their normal working. You should not indulge in them. By observing body, mind and intellect, you will go beyond the religion of them, and their actions will not bind you again. This is the practice of pratyahara."
So, the guru in the material sense also observes his disciple and firstly he treats him by giving training in asanas, pranayama, pratyahara, etc. to purify his body, mind and intellect as well as to enable him to become observer of their activities. If this is not done, tensions in mind, body and intellect will prevent a disciple from understanding the real Self, as well as being successful in worldly affairs.
In the company of the guru everybody wants to soar up into the higher planes of consciousness. One feels that if he gets guru's grace, his kundalini will be awakened, and he may also become guru of so many. But, this is a very difficult job because, without purifying body, mind and intellect, and without knowing the scientific approach, one cannot find God or himself. To this effect. Krishna says:
"Out of thousands, few try for siddhi. Out of those few practising for siddhi, only some get Siddhi, and of those who get siddhi, rarely one comes to know my reality." (7/3)
Firstly, guru acts at a therapeutic level. He knows that emotional conflicts cause the diseases of body, mind and intellect. Gradually, he removes them by the practices of hatha yoga and raja yoga. Not only this, by establishing yama and niyama, he creates an ashram atmosphere and also regulates the diet, which is actually required by the digestive system. In this way, guru makes a new and healthy personality which is able to perform magic in the outer world.
By the guru's example, we learn the scientific approach of karma yoga. Everybody is doing work for his own bread and butter, but how many are really doing karma yoga? Karma yoga is a scientific practice, as explained by Lord Krishna to Arjuna:
"I am telling a most secret thing, by knowing which you will be free from the bondages of the world. And that is not only knowledge, but knowledge with science which I am telling you." (9/1)
Knowledge only remains a philosophy, which is of no practical use for a worldly man. But it is the knowledge which is practical in a particular way which cannot bind us to the material world.
Here, guru Krishna says to Arjuna:
"Whatever you do, whatever you eat, whatever you give and take, whatever sadhana you are performing, do it with dedication to me." (9/27)
And what will happen?
"You will be free from the bondages of both good and bad work." (9/28)
Guru teaches us the scientific approach to karma yoga, which, is not doing any work for ourself. We only work for the ashram or the guru. In the spirit of karma yoga, we learn how to live a perfect life by which detachment automatically develops. That was why Arjuna could face the battlefield again, and this dedication is a representation of bhakti. Karma and bhakti are associated with knowledge. This is the ultimate path of shanti, ananda or freedom from all bondages of society and material life.
When a disciple follows the above path, he automatically reaches the devotional height where nothing remains incomplete, and there is victory, the ultimate victory:
"Where there are guru and disciple both, Victory is sure." (18/78)