From the Arab peoples of Ishmael, the man Muhammad, destined by birth to be the Holy One according to some Muslims, became the rasul, or messenger, of God's revelation. Muhammed wrote down his revelations in the Qur'an, the Islamic scriptures considered to be the literal dictation of the word of God by Mohammad from the angel Gabriel.
Islam is defined by the Qur'an and the Hadith, an expansion of the Qur'an and Muhammad's teaching and actions. Islam revolves around a subjugation to one God (monotheism) for the safety and peace of humanity. The cities of Mecca and Medina are also pivotal to Islam as they were the two centers for Mohammad's teachings.