Ahimsa, or non-violence, has been a highly extolled virtue throughout Indian history. In fact, it is as old as the Ṛigveda itself. Even during the Vedic period, when animal sacrifices existed, the animal was rendered unconscious before being killed, so that it did not suffer. Prayers were offered to ward off the effects of the sin of killing an animal. The Upanishads refer to ahimsa as an ethical discipline and emphasize the need for cultivating compassion, as corollary to ahimsa. The Mahābhārata often calls 'ahimsa' the highest dharma (ahimsā paramo dharmah). The Purāṇās and Dharma shāstrās extol it in glowing terms. Ahimsa is also described as the gateway to dharma. The Yogasutrās of Patanjali list it as the first virtue to be cultivated by a yoga aspirant.
