The Qur'an had begun to develop a primitive just war theory. In the steppes, aggressive warfare was praiseworthy; but in the Qur'an, self-defense was the only possible justification for hostilities and the preemptive strike was condemned.5 War was always a terrible evil, but it was sometimes necessary in order to preserve decent values, such as freedom of worship. Even here, the Qur'an did not abandon its pluralism: synagogues and churches as well as mosques should be protected. The Muslims felt that they had suffered a fearful assault; their expulsion from Mecca was an act that had no justification. Exile from the tribe violated the deepest sanction of Arabia; it had attacked the core of the Muslims' identity.