The Arabic word jihad means "struggle" or "exertion" and refers to any spiritual, moral or physical struggle. Upon returning from a battle, the Prophet Muhammad is reported to have said, "We are returning from the lesser jihad to the greater jihad—jihad against the self." For Muslims, jihad means struggle in the cause of God, which can take many forms. In the personal sphere, efforts such as obtaining an education, trying to quit smoking, or controlling one's temper are forms of jihad.

Jihad as a military action is justified in two cases: struggle to defend oneself, or others, from aggression and struggle for freedom of religion and justice. The Qur'an says "Tumult and oppression are worse than killing" (2:217), and therefore must be thwarted. Human beings as responsible agents of God on earth are compelled to exert themselves to protect the oppressed and strive to create righteous societies.

Systematic, forced conversion to Islam is a historical myth. Muslims defeated hostile forces (Byzantines and Persians for example) and gained control of new lands where Islamic rule was established, yet non-Muslim inhabitants were not forced to become Muslims. Islam clearly condemns such actions: "There is no compulsion in religion." (Qur'an, 2:256) For various reasons, and in the course of time, many non-Muslims did find the message of Islam appealing, however, and converted to Islam, resulting ultimately in the transformation of society at all levels.

Because jihad is a highly nuanced concept, and because the term stems from an Arabic root meaning "struggle," the term "holy war" is an inappropriate rendering or definition.