Following is an overview of the basic tenets of Islam -- not Islamic "fundamentalism," "extremism," "fanaticism," "Islamo-fascism," or "Islamism," but Islam proper, Islam in its orthodox form as it has been understood and practiced by right-believing Muslims from the time of Muhammad to the present.
(A) The Five Pillars of Islam
The five pillars of Islam constitute the most basic tenets of the religion. They are:
1. Faith (iman) in the oneness of Allah and the finality of the prophethood of Muhammad -- indicated by the declaration [the Shahadah] that, "There is no God but Allah and Muhammad is the messenger of Allah."
2. Keeping of the five scheduled daily prayers (salah)
3. Almsgiving (zakat)
4. Fasting (sawm)
5. Pilgrimage (hajj) to Mecca for those who are able
The second through fifth pillars -- prayer, almsgiving, fasting, pilgrimage -- are aspects shared by many religions. The finality of the prophethood of Muhammad, however, is unique to Islam. To understand Islam and what it means to be a Muslim, we must come to understand Muhammad as well as the revelations given through him by Allah, which make up the Quran.
(B) The Quran -- the Book of Allah
According to Islamic teaching, the Quran was transmitted as a series of revelations from Allah through the Archangel Gabriel to the Prophet Muhammad, who then dictated it to his followers. Muhammad's companions memorized fragments of the Quran and transcribed them on whatever material was at hand; these were later compiled into book form under the rule of the third Caliph, Uthman, some years after Muhammad's death.
The Quran is about as long as the Christian New Testament. It comprises 114 suras (not to be confused with the Sira, which refers to the life of the Prophet) of varying lengths, which may be considered chapters. According to Islamic doctrine, it was around 610 AD in a cave near the city of Mecca (now in southwest Saudi Arabia) that Muhammad received the first revelation from Allah. The revelation merely commanded him to "recite" or "read" (Sura 96); the words he was instructed to utter were not his own but Allah's. Over the next twelve or so years in Mecca, Muhammad received other revelations that constituted a message to the inhabitants of the city, exhorting them to forsake their pagan ways and turn in worship to the one Allah.
While in Mecca, though he condemned paganism (for the most part), Muhammad showed great respect for the monotheism of the Christian and Jewish inhabitants. Indeed, the Allah of the Quran claimed to be the same God worshipped by Jews and Christians, who now revealed himself to the Arab people through his chosen messenger, Muhammad. It is the Quranic revelations that came later in Muhammad's career, after he and the first Muslims left Mecca for the city of Medina, that transformed Islam from a relatively benign form of monotheism into an expansionary, military-political ideology that persists to this day.
A critically important principle of Quranic interpretation is known as "abrogation" (al-naskh wa al-mansukh). This principle holds that verses revealed later in Muhammad's career "abrogate" -- i.e., cancel and replace -- earlier ones whose instructions they may contradict. Thus, passages revealed later in Muhammad's career, in Medina, overrule passages revealed earlier, in Mecca. The Quran itself lays out the principle of abrogation:
2:106. Whatever a Verse (revelation) do We [Allah] abrogate or cause to be forgotten, We bring a better one or similar to it. Know you not that Allah is able to do all things?
It seems that 2:106 was revealed in response to skepticism directed at Muhammad that Allah's revelations were not entirely consistent over time. Muhammad's rebuttal was that "Allah is able to do all things" -- even change his mind.
Though the Quran was revealed to Muhammad sequentially over some twenty years' time, it was not compiled in chronological order. When it was finally collated into book form under Caliph Uthman, the suras were ordered from longest to shortest with no connection whatever to the order in which they were revealed or to their thematic content. The Meccan suras, revealed at a time when the Muslims were vulnerable, are generally benign; the later Medinan suras, revealed after Muhammad had made himself the head of an army, are bellicose.
Consider, for example, Sura 109, which was revealed in Mecca:
109:2. "I worship not that which you worship,
109:3. "Nor will you worship that which I worship.
109:4. "And I shall not worship that which you are worshipping.
109:5. "Nor will you worship that which I worship.
109:6. "To you be your religion, and to me my religion (Islamic Monotheism)."
In contrast, consider 9:5, commonly referred to as the "Verse of the Sword," revealed in Media, toward the end of Muhammad's life:
9:5. Then when the Sacred Months ... have passed, then kill the Mushrikun [unbelievers] wherever you find them, and capture them and besiege them, and prepare for them each and every ambush. But if they repent and perform As-Salat [the Islamic ritual prayers] and give Zakat [alms], then leave their way free.
Having been revealed later in Muhammad's life than Sura 109, the Verse of the Sword abrogates the peaceful injunctions of the former. Sura 8, also revealed long after Sura 109, reveals a similar theme:
8:39. And fight them until there is no more Fitnah [disbelief and polytheism: i.e. worshipping others besides Allah] and the religion [worship] will all be for Allah Alone [in the whole of the world].
8:67. It is not for a Prophet that he should have prisoners of war [and free them with ransom] until he had made a great slaughter [among his enemies) in the land.
The Quran's commandments to Muslims to wage war in the name of Allah against non-Muslims are unmistakable. They are, furthermore, absolutely authoritative as they were revealed late in the Prophet's career and so cancel and replace earlier instructions to act peaceably. Without knowledge of the principle of abrogation, Westerners commonly misread the Quran and misdiagnose Islam as a "religion of peace."
(C) The Sunnah -- the "Way" of the Prophet Muhammad
In Islam, Muhammad is considered al-insan al-kamil (the "ideal man"). He is not considered divine, nor is he worshipped (no image of Muhammad is permitted lest it encourage idolatry), but he is the model par excellence for all Muslims in how they should conduct themselves. It is through Muhammad's personal teachings and actions -- which make up the "way of the Prophet," the Sunnah -- that Muslims discern what is a good and holy life. Details about the Prophet -- how he lived, what he did, his non-Quranic utterances, his personal habits -- are indispensable knowledge for any faithful Muslim.
Knowledge of the Sunnah comes primarily from the hadiths ("reports") about Muhammad's life, which were passed down orally until codified in the eighth century AD, some hundred years after Muhammad's death. The hadiths comprise the most important body of Islamic texts after the Quran; they are basically a collection of anecdotes about Muhammad's life believed to have originated with those who knew him personally. There are many thousands of hadiths, some running to multiple pages, some barely a few lines in length. When the hadiths were first compiled in the eighth century AD, it became obvious that many were inauthentic. The early Muslim scholars of hadith labored to determine which hadiths were authoritative and which were suspect. The most reliable and authoritative collection of hadiths was compiled by Sahih Al-Bukhari, and is recognized as authentic by all schools of Islamic scholarship.
Because Muhammad is himself the measuring stick of morality, his actions are not judged according to an independent moral standard but rather establish what the standard for Muslims properly is -- regardless of whether those actions may offend the sensibilities of modern-day non-Muslims. Some examples include:
Volume 7, Book 62, Number 88: The Prophet wrote the [marriage contract] with Aisha while she was six years old and consummated his marriage with her while she was nine years old and she remained with him for nine years [i.e. till his death].
Volume 8, Book 82, Number 795: The Prophet cut off the hands and feet of the men belonging to the tribe of Uraina and did not cauterise [their bleeding limbs] till they died.
Volume 2, Book 23, Number 413: The Jews [of Medina] brought to the Prophet a man and a woman from amongst them who have committed illegal sexual intercourse [adultery]. He ordered both of them to be stoned [to death], near the place of offering the funeral prayers beside the mosque.
Volume 1, Book 2, Number 25: Allah's Apostle was asked, "What is the best deed?" He replied, "To believe in Allah and His Apostle [Muhammad]. The questioner then asked, "What is the next [in goodness]?" He replied, "To participate in Jihad [religious fighting] in Allah's Cause."
In Islam, there is no "natural" sense of morality or justice that transcends the specific examples and injunctions outlined in the Quran and the Sunnah. Because Muhammad is considered Allah's final prophet and the Quran the eternal, unalterable words of Allah himself, there is also no evolving morality that permits the modification or integration of Islamic morality with that from other sources. The entire Islamic moral universe devolves solely from the life and teachings of Muhammad.
Along with the reliable hadiths, a further source of accepted knowledge about Muhammad comes from the Sira (life) of the Prophet, composed by one of Islam's great scholars, Muhammad bin Ishaq, in the eighth century AD.
Muhammad's prophetic career is meaningfully divided into two segments: The first was in Mecca, where he labored for fourteen years to make converts to Islam; where he preached repentance and charity; and where he was harassed and rejected by those around him. The second phase began in 622, when the Prophet was more than fifty years old. He and his followers made the Hijra (emigration or flight) from Mecca to the oasis of Yathrib -- later renamed Medina -- some 200 miles to the north. He would spend the final ten years of his life in this region, where he became an able commander and strategist who systematically conquered and killed those who opposed him.
Shortly before Muhammad fled the hostility of Mecca, a new batch of Muslim converts pledged their loyalty to him on a hill outside Mecca called Aqaba. The Sira conveys the significance of this event:
Sira, p208: When God gave permission to his Apostle to fight, the second [oath of allegiance at] Aqaba contained conditions involving war which were not in the first act of fealty. Now they [Muhammad's followers] bound themselves to war against all and sundry for God and his Apostle, while he promised them for faithful service thus the reward of paradise.
That Muhammad's nascent religion underwent a significant change at this point is plain. The scholarly Ishaq, who penned the foregoin passage, clearly intends to impress on his Muslim readers that, while in its early years Islam was a relatively tolerant creed that would "endure insult and forgive the ignorant," Allah soon required Muslims "to war against all and sundry for God and his Apostle." The Islamic calendar testifies to the paramouncy of the Hijra by setting year one from the date of its occurrence. The year of the Hijra, 622 AD, is considered more significant than the year of Muhammad's birth or death or that of the first Quranic revelation because Islam is first and foremost a political-military enterprise. It was only when Muhammad left Mecca with his paramilitary band that Islam achieved its proper political-military articulation.