Islam (1.2 billion adherents) is one of the major world religions that, along with Christianity (1.9 billion adherents) and Judaism (14 million adherents), teaches monotheism which is the doctrine that there is only one God in all existence. Like Christianity and Judaism, Islam traces its roots back to the patriarch Abraham (Gen. 12). The word "Islam" means "surrender" or "submission".1 It comes from the root word "salem" which means "surrender." A Muslim (or Moslem - which means one who surrenders to God) is an adherent of Islam, a religion with precise theological doctrines about God, judgment, heaven, hell, angels, prophets, salvation, etc.
The Arabic word for god is "allah" which has become a kind of name of God in Islam. Islam teaches that Allah is the one and only deity in all existence (Qur'an 5:73, 112:1-4). He is supreme, all-knowing (40:20), ever-present, different from all of creation (3:191), and in complete control of all things. According to Islam, Allah created the universe in six days (2:29, 25:61-62), and all that is in it continues to exist by his permission and will. Allah is non-Trinitarian (5:73), but he is absolute and eternal.
The Koran (or Qur'an, which means "the reading" in Arabic) is the sacred book of Islam and is broken up into 114 chapters called Suras which cover the subjects of ethics, history, law, and theology. It is highly revered by Muslims as the direct, literal word of God. The Qur'an (also spelled Quran and Koran) was supposedly delivered by the angel Gabriel (also known as the Holy Spirit) to Muhammad over a 23-year period after Muhammad's initial encounter with Gabriel in a cave when he was 40 years old. Muslims consider Muhammad (full name of Muhammad Ibn Abdullah) to be the final prophet of God to the world. Muhammad was born in A.D. 570 in Mecca and died in A.D. 632 after being poisoned.
Second only to the Islamic belief in the unity/oneness of God is the supremacy of Muhammad as Allah's prophet. In Islam, to become a believer you must recite the shahada: "There is no God but Allah and Mohammed is his prophet."
It's important to note the equality between Allah and Mohammed in the shahada. The Muslims will tell you that Mohammed is not equal to God, but in order to be saved in Islam, you must have faith not only in the Muslim God, but also in Mohammed as the only prophet.
Islam acknowledges that many prophets preceded Muhammad. The major ones are Noah, Abraham, Moses, David, and Jesus. These prophets gave revelations from God which were written as scriptures, mainly, the Old and New Testaments. These predecessors to Muhammad are considered great prophets who spoke for God to specific people and whose message was meant for that time. Jesus, according to Islam, was simply one of many prophets. Therefore, Muslims deny the Christian doctrine of the deity of Jesus, the need for His atoning sacrifice (4:157-158), the Trinity (5:73), and much more. According to Islam, no sacrifice is needed to be forgiven, only faith in Allah, sincere repentance, and obedience to Islamic law (3:135, 7:8-9, 21:47, 49:14, 66:8-9). In fact, in Islam, the greatest of sins, called shirk, is to attribute "partners" to God. In other words, to say that God is a Trinity of persons is an unforgivable sin to a Muslim.
In addition to the Qur'an is the Hadith. It is another source of authority in Islam though it is second to the Qur'an. The Hadith is a collection of the sayings and deeds of Muhammad as recorded by his companions. They are oral traditions and are considered authoritative and instructive as commentaries and applications of Qur'anic principles and contain additional principles not found in the Qur'an. According to Islam, the Hadith are the inspired truths of God transmitted to us in the style and words of Muhammad. By contrast, the Quran is supposed to be the exact words of Allah, which are supposed to be protected from corruption by him.
In Islam, all Muslims are united by the common faith irrespective of class, location, race, or gender. Therefore, they have a special bond of unity and equality. The primary "truth" of Islam is found in the first pillar of Islam known as the shahada: "There is no true God except Allah and Muhammad is the Messenger of Allah."
Islamic theology also teaches that angels were created from light and jinn are another race of beings, created from fire, who are invisible yet all around us, there is an eternal judgment to Paradise for the good and Hell for the bad, Jesus was never crucified and that drinking alcohol is forbidden as is gambling.
Within the first two centuries after its inception in Arabia, Islam spread very quickly, often aided by the sword (jihad),2 into North Africa, up through Europe to Spain, and east to India. Presently, about 1 billion people are Muslim world-wide with adherents on every continent and nation. It is perhaps the world's fastest-growing religion and second in size only to Christianity.
Like most ancient religions, there are sects. Islam is no different. The major sects in Islam are the Sunni and the Shiites. The Sunni are the largest group and comprise about 90% of all Muslims. The Shiites, though smaller in number, are significant in Islamic history and presently occupy the lands of Iran, Iraq, Lebanon, Syria, Saudi-Arabia, Yemen, and Persian Gulf states.
The most important place of worship for the Muslim is the Mosque, which is always pointed towards Mecca (the birthplace of Muhammad) and is located in Saudi Arabia. All Muslims must face Mecca during their times of prayer because in Mecca there is the Ka'aba, a cube structure allegedly built by Abraham which contains a sacred stone. When a Muslim is in Mecca, he or she faces the Ka'aba.
Many Muslims hope for shari'ah, the complete rule of Islamic law in the world. To this end, Muslims are seeking more converts, attacking other religious systems both by the sword and by word, moving into every nation, and seeking political power wherever they can achieve it. Islam is a growing and aggressive religion that seeks to submit everyone on the planet to its rule.