…At the physical level, the word ahimsa is relative. A surgeon cuts the body for the good of the patient. His motive is to heal. This is an act of ahimsa. On the other hand, a murderer using a knife commits a definite act of violence because his motive is to hurt or kill. The same action can be dharmika or adharmika depending upon whether one is acting to integrate or destroy.

Now a very important question arises. In the Gita, Lord Krishna teaches about non-injury (ahimsa). How is it then that He asks Arjuna to fight? Many people wonder, “How can this war be considered dharmika (righteous) while at the same time observing the law of ahimsa?”

Earlier we spoke about dharma as it pertains to physical health. When the body is in a healthy condition, we will live comfortably. There is no need for medical treatment of any kind. But suppose the body develops a disease? Then possibly some medications or minor surgery may help. But if the disease is very serious, major surgery or even amputation may be the only solution.

In the same way, if everyone is living happily and peacefully in society, then there is no need for war. But, as in the case of the Mahabharata, the evil, battle-hungry Duryodhana became strong and powerful, much like a cancer, whose growth was out of control. Small remedies could not fix the problem. If people like him are not removed from society, good people suffer and disintegration of the society is certain. Therefore, in such situations the ideal of ahimsa and a righteous war go together.

…Dharma at the individual level is also different from that practiced at the community level. As individuals we may not carry any weapons, trying always to respond with peace and non-injury. However, if one is the secretary of defence of a country then that person cannot allow anyone to jeopardise its peace and he must be prepared to defend the national security. Therefore, dharma has to be understood in its totality.

May get dissapointed in this Kaliyuga if you really search for a guru. You know the concept of Guru is a relative one. There are so many types of the Gurus or a single Guru assumes the different types depending upon the ‘Patra’ of ‘Shishya’. One of the Guru knowing Brahmvidya is Maharshi Ved Vyas. You can learn from him by studying his scriputures so abundent but only by reconciling the apparently contradictory chords stuck in his literature.

I think he has blessed me to my satisfaction and I am in a position to understand the ‘Secret of Universe’.

http://idealworldkrishna.blogspot.com/

The need to approach a spiritual master as given in Upanishads “The age-old Vedic literature of India tells us clearly how to enter into spiritual life: “One must approach a spiritual master if he desires spiritual realization” (Mundaka Up.. 1.2.12). Also, “The aspirant should surrender to a spiritual master if he is genuinely inquisitive about the highest goal of life” (Bhag. 11.3.21).”

Krishna has stressed this point in Bhagavad Gita a couple of times. Refer the verse BG 4.34 (Chapter 4 Verse 34) http://vedabase.net/bg/4/34/en (“Bhagavad Gita As It Is” by AC Bhaktivedanta Swami Prabhupada)

also some references from Puranas about the neccessity of approaching the spiritual master:

extracted from link : http://www.krishna.com/finding-genuine-guru