The word Islam means “submission.” Its central tenet is submission before the will of God, as revealed to humanity by Muhammad. An aspect of Islam that distinguishes it from Judaism and Christianity is that the Koran has a single point of origin, the recitations of Muhammad himself, and it is believed by Muslims that it cannot be translated from Arabic and remain the "real" holy book. In other words, translations can be made for the sake of education, but every word in the Koran, spoken in the classical Arabic of Muhammad's day, is believed to be that true language of God - according to traditional Islamic belief, the angels speak Arabic in paradise.
According to Islam, Muhammad was the last in the line of prophets stretching back to Abraham and Moses and including Jesus, whom Muslims consider a major prophet and a religious leader, but not actually divine. Muhammad delivered the “definitive version” of God's will as it was told to him by Gabriel on the mountainside. The core tenets of Islamic belief are referred to as the "five pillars":
- There is only one God and Muhammad is his prophet.
- Each Muslim must pray five times a day, facing toward the holy city of Mecca.
- During the holy month of Ramadan, each Muslim must fast from dawn to sundown.
- Charity should be given to the needy.
- If possible, at least once in his or her life, each Muslim should undertake the Haaj: the pilgrimage to the holy city of Mecca.
In turn, a central concept of Islam is that of the worldwide community of Muslims, the Ummah, meaning "community of believers." The Ummah was a central idea from the lifetime of Muhammad onward, referring to a shared identity among Muslims that is supposed to transcend differences of language, ethnicity, and culture. All Muslims are to follow the five pillars, just as all Muslims are to meet other members of the Ummah at least once in their lives while on pilgrimage.
One term associated with Islam, Jihad, has sparked widespread misunderstanding among non-Muslims. The word itself simply means "struggle." It does mean “holy war” in some cases, but not in most. The concept of Jihad revolves around the struggle for Muslims to live according to Muhammad's example and by his teachings. Its most common use is the “jihad of the heart,” of struggling to live morally against the myriad corrupting temptations of life.
The Koran itself was written down starting during Muhammad’s life (his revelations were delivered over the course of about twenty years, and were initially transmitted orally). The definitive version was completed in the years following his death. Of secondary importance to the Koran is the Hadith, a collection of stories about Muhammad’s life, behavior, and sayings, all of which provided a model of a righteous and ethical life. In turn, in the generations following his death, Muslim leaders created the Sharia, the system of Islamic law based on the Koran and Hadith.