Ahimsa (Sanskrit: अहिंसा, IAST: ahiṃsā, lit. 'nonviolence'; Pali pronunciation: [avihiṃsā]), is an ancient Indian principle of nonviolence which applies to all living beings. It is a key virtue in the Dhārmic religions: Jainism, Buddhism, Hinduism, and Sikhism.
Ahimsa is one of the cardinal virtues of Jainism, where it is first of the Pancha Mahavrata. It is also the first of the five precepts of Buddhism. Ahimsa is a multidimensional concept, inspired by the premise that all living beings have the spark of the divine spiritual energy; therefore, to hurt another being is to hurt oneself. Ahimsa has also been related to the notion that any violence has karmic consequences. While ancient scholars of Hinduism pioneered and refined the principles of Ahimsa, the concept also reached an extraordinary development in the ethical philosophy of Jainism. Lord Parsvanatha, the twenty-third tirthankara of Jainism, revived and preached the concept of non-violence in the 9th century BCE. Mahavira, the twenty-fourth and the last tirthankara, further strengthened the idea in the 6th century BCE. Between the 1st century BCE and 5th century CE, Valluvar emphasized ahimsa and moral vegetarianism as virtues for an individual, which formed the core of his teachings. Perhaps the most popular advocate of the principle of Ahimsa was Mahatma Gandhi.
Ahimsa's precept of 'cause no injury' includes one's deeds, words, and thoughts. Classical Hindu texts like the Mahabharata and Ramayana, as well as modern scholars, debate principles of Ahimsa when one is faced with war and situations requiring self-defence. Historical Indian literature has in this way contributed to modern theories of just war and self-defence.