Ahimsā or non-violence has been a highly extolled virtue throughout Indian history. In fact, it is as old as the Ṛgveda itself. To quote one mantra: mā vo ghnataṁ mā śapatam prati voce deva yantam, ‘Return not blow for blow, nor curse for curse, neither meanness for base tricks. Shower blessings instead’ (Ṛgveda Saṁhitā 4.1.8). Even during the Vedic period, when animal sacrifices existed and the animals were believed to attain heaven, the animal meant for immolation was made unconscious before being killed, so that it did not suffer. Prayers were offered and expiations done to ward off the effects of the sin of killing the animal which was inevitable in the sacrifices (vide Taittirīya Brāhmaṇa 184.108.40.206).
Coming to the Upaniṣads, the earliest reference to ahiṁsā as an ethical discipline is found in the Chāndogya Upaniṣad (3.17.4; 8.15.1) where it has been bracketed with truth. The Bṛhadāraṇyaka Upaniṣad (5.2.3) emphasises the need for cultivating compassion, the corollary of ahiṁsā. The Mahābhārata often calls it the highest dharma (ahiṁsā paramo dharmaḥ—1.11.13-14). The purāṇas and dharma-śāstras extol it in glowing terms. It is even termed as ‘sanātanadharma’ (the ancient religion) by some purāṇas like the Brahmāṇda and Matsya, and also des-cribed as the gateway to dharma. The Yogasūtras of Patañjali (2.30) lists it as the first virtue to be cultivated by the aspirant for yoga.
Ahiṁsā is not injuring other living beings in thought, word and deed. This is the ideal to be relentlessly pursued by those who have dedicated their lives to the realization of the ātman (the Self). For them it is a mahāvrata (great vow). Others should practise it as far as possible.
That physical injury or harsh words inflict pain and suffering is easily understood. However, what is not so easily understood is that inimical thoughts that one harbours against others harm both. This is a fact—whether one concedes it or not—as all minds, being parts of the one cosmic mind, are interconnected, so that a thought arising in one mind concerning another mind can always cause a reaction in the other, good for good and bad for bad.
Ahiṁsā can never be practised perfectly without its complement, love. They are two sides of the same coin. Anyone who has practised it effectively radiates a wonderful atmosphere of peace. Even animals with mutual and natural enmity, if they come within the orbit of this influence, live in peace and harmony (vide Yogasūtras of Patañjali 2.35).
Some of the purāṇas (vide—Brahmāṇḍa 2. 36. 188) recommended the killing of tyrants and desperados and opined that such killing is no hiṁsā at all, since many will live in happiness and peace by their death.
Buddhism and Jainism have accorded ahiṁsā the topmost place among virtues to be cultivated. Jainism has carried it to rather extreme lengths.