Ahimsa is one of the ideals of Hinduism. It means that one should avoid harming any living thing, and also avoid the desire to harm any living thing. Ahimsa is not just non-violence – it means avoiding any harm, whether physical, mental or emotional.
Hindus oppose killing for several reasons. Belief in karma and reincarnation are strong forces at work in the Hindu mind. They full well know that any thought, feeling or action sent out from themself to another will return to them through yet another in equal or amplified velocity. What we have done to others will be done to us, if not in this life then in another. The Hindu is thoroughly convinced that violence which he commits will return to him by a cosmic process that is unerring.
To do harm to others is to do harm to oneself. You are he whom you intend to kill. You are he whom you intend to dominate. We corrupt ourselves as soon as we intend to corrupt others. We kill ourselves as soon as we intend to kill others.