Political aspects of Islam are derived from the Quran, ḥadīth literature, and sunnah (accounts of the sayings and living habits attributed to the Islamic prophet Muhammad during his lifetime), the history of Islam, and elements of political movements outside Islam. Traditional political concepts in Islam include leadership by elected or selected successors to Muhammad, known as Caliphs in Sunnī Islam and Imams in Shīʿa Islam; the importance of following the Islamic law (sharīʿa); the duty of rulers to seek consultation (shūrā) from their subjects; and the importance of rebuking unjust rulers.