Bhagavad Gita is all about preaching of peace and maintaining sanctity even in most adverse circumstances. Indulging in spirituality detailed in Bhagavad Gita we can all the time reach the hidden underlying truth of statements made by people.
We come across different shades of people all the time of whom some may be good and others bad. How do we recognize the bad amongst the good few? Indulging in spirituality we can do that.
If we encounter an enemy whose intentions are sinister then as per Bhagavad Gita it is tit for tat. We just cannot forgive the intruder. Forgiveness can never be practiced in such circumstances.
To save millions of lives of countrymen and soldiers Chanakya (the most able administrator in the entire history of mankind) got 100 kings eliminated in one night. This is what should be done with the enemy of the state.
Most fights world over ensued from bloated egos of individuals. If the enemy at the door is stronger than us still we have to retaliate with full force head-on. This happened with Pandavas. Before the battle of Mahabharata the Pandava chieftain Arjuna tried his best to make amends with his arch rivals Kauravas, who were also his close cousins, relatives and friends.
It was then Lord Krishna intervened. Lord Krishna also tried his best as an avatar (God manifest in human form) but he also failed. Kauravas were hell-bent on capturing the Pandava kingdom. In such circumstances Arjuna expressed cowardice. Lord Krishna being the knower of all finally dispensed sermon of Bhagavad Gita to Arjuna!
The only submission of Lord Krishna was that Arjuna primarily was a spirit, a soul atman and not the manifest physical human form. Furthermore he was the chieftain who represented more than million countrymen and soldiers. When facing the enemy consisting of close cousins, relatives and friends he just could not feign ignorance and withdraw from the battle.
In a short while Arjuna realized his folly and finally prepared himself to fight the enemy head-on. Lord Krishna impressed upon Arjuna that demands of Kauravas were irrational, unacceptable. The only solution in such circumstances was a full-scale fight.
Mahatma Gandhi practiced Ahimsa (so called non-violence) when fighting the British, the enemy within. On his advice the British rained lathies on Lala Lajpat Rai, so much so that the Crusader of truth eventually succumbed to British lathies. For the untimely death of Lala Lajpat Rai Mahatma Gandhi is squarely to blame. How can Ahimsa be practiced when facing a deadly enemy?
When Alexander approached India Chanakya recognized his nefarious designs. Alexander was rendered a brutal defeat even before the fight only due to foolproof planning of Chanakya.
When facing the enemy head-on, one must never practice Ahimsa (so called non-violence) advises Lord Krishna in Bhagavad Gita. Furthermore to re-establish Dharma (righteousness), to remove the rot in the society a battle of Dharma is sometimes necessitated. Battle of Mahabharata is no ordinary battle; it is a battle to re-establish Dharma.
As everything in Bhagavad Gita is allegorical, a fight ensues inside us between positive and negative forces of nature. The positive can never subdue its position and accept defeat. Lord Krishna in Bhagavad Gita says always to fight the enemy head-on. No matter how appalling the circumstances, one must never accept defeat in life.