Islam, the strict monotheistic faith that is based on the teachings of Muhammad, rests on the principle of the oneness and omnipotence of God (Allah). Muslims believe that Muhammad was the last of the prophets, completing the work begun by Abraham, Moses, and Jesus. The Qur’an holds that the holy writings of both Jews and Christians represent divine revelation, but it claims that both Jews and Christians tampered with the books of God.

Muslims believe that they worship the same God as Jews and Christians. Islam appropriates much of the Old and New Testaments of the Bible but often retells the narratives with significant shifts in meaning. Muhammad insisted that he was not preaching a new message; rather, he was calling people back to the one true God, urging his contemporaries to reform their lives, to return to the faith of Abraham, the first monotheist.

The Qur’an prescribes a strict code of moral behavior. A Muslim must recite the profession of faith in God and in Muhammad as his prophet: “There is no God but God, and Muhammad is his Prophet.” A believer must also pray five times a day, fast and pray during the sacred month of Ramadan, make a pilgrimage (hajj) to the holy city of Mecca once during his or her lifetime, and give alms to the Muslim poor. These fundamental obligations are known as the Five Pillars of Islam.

Islam forbids alcoholic beverages and gambling. It condemns usury in business — that is, lending money and charging the borrower interest — and taking advantage of market demand for products by charging high prices. Muslim jurisprudence condemned licentious behavior by both men and women and specified the same punishments for both.

Like the Christian Judgment Day, on the Islamic Judgment Day God will separate the saved and the damned. The Qur’an describes in detail the frightful tortures with which God will punish the damned and the heavenly rewards of the saved and the blessed.