Shrimad Bhagwat Geeta Chapter 1 shlok 36-37

Arjun’s reluctance to harm his relatives continues to be expressed with the phrase “even though.” He addresses Shree Krishna as Janardhana, the sustainer of the populace, saying, “Even though I am well aware of their willingness to attack us, I still believe that it would be a sinful act to take the lives of my uncle Dhritarashtra’s sons.”

Switching to address Krishna as Madhav, the husband of Goddess Lakshmi, Arjun adds, “It is not appropriate for us to harm our own cousins and relatives. How can we ever find happiness in committing such an act?”

In most circumstances, taking someone’s life is considered a grave sin, leading to guilt and remorse. The Vedas state, “mā hinsyāt sarvā bhūtāni,” which means “Do not harm any living being.” Unless absolutely necessary in an extreme situation, violence in any form is deemed a sin, and non-violence is considered a superior virtue. In Arjun’s case, even though the wrongdoings of the enemy were unpardonable, he was unwilling to kill them due to his belief in the immorality of such actions.

However, according to Vasiṣhṭh Smṛiti (verse 3.19), there are six circumstances in which it is considered acceptable to take a life. This includes self-defense to protect oneself from enemies who have: set fire to their property, attempted to poison them, conspired to commit murder, looted their wealth, kidnapped or dishonored their women, or seized their kingdom. Even the Manu Smṛiti (8.351) mentions that it is not considered a sin to kill an attacker in self-defense.