The Qur’an, the holy book of Islam, contains the revelations from Allah to the prophet Muhammad. The Qur’an was revealed in Arabic, a language that therefore holds a special place of respect and admiration for all Muslims. The Qur’an contains instructions for governing every aspect of human life.

Under the caliph Omar the suras, or verses, were codified and arranged in order of ascending length with the shortest first. The longer ones, usually revealed in Medina, tend to pertain to matters of civil government and law; thus the Qur’an does not separate matters of religion from those of the state.

The Qur’an’s main focal point is the existence of one God who is omnipotent. Muslims accept all of the prophets of the Old and New Testaments with Muhammad as the last and greatest of the prophets.

Qur’anic injunctions are a combination of forgiveness and obedience. The Qur’an deals with proper modes of behavior for all humankind including dietary laws (pork and alcohol are forbidden), adultery (four witnesses are necessary), and slavery (Muslims are to treat slaves kindly and laws are set down for the manumission of slaves).

Women are given specific rights, including the right to own and inherit property, rights that women did not achieve in the West for many centuries. Islam improved the lot and rights of women from those of the era.

The caliph Uthman declared one text of the Qur’an as the one and only definitive copy and all others were suppressed; because of both Omar and Uthman there is therefore only one accepted text of the Qur’an, unlike the numerous texts of the Bible. For millions of Arabic speakers, Muslims and non-Muslims alike, the language of the Qur’an remains the model for grammar, syntax, and literary beauty.

Muslims also consider the Sunna, the collection of the customs of the Prophet, as guidelines for proper behavior. The Hadith, the collection of sayings and traditions of the prophet Muhammad, is another guideline for the community.

Several different texts of the Hadith exist. Some hadiths are considered more reliable than others. Reliability is gauged by who transmitted the saying or deed of the Prophet and his companions. Firsthand accounts are considered more valid than those passed on by third or fourth parties or by those whose veracity is held in doubt.

The chain of transmission is known as isnad. In general, the Shi’i criteria for validating hadith are somewhat more flexible and broader than those of the majority, orthodox Sunnis. Muslim scholars have produced massive volumes on the Hadith with various interpretations of given sayings and traditions.