Overview of Islam

Founder

Muhammad was born around 570 CE in Mecca, an international city located on the coast of the Red Sea, and he grew up there. Mecca was a city with active trade, and among its industries, religious activities were particularly important. He was born into the prominent Hashim clan of the Quraysh tribe, born into a wealthy family, but became an orphan at the age of six and subsequently grew up under the protection of his grandfather and uncle. Because of this background, he is said to have had great concern for widows and orphans.

At the age of 25, Muhammad married Khadijah, a wealthy widow and merchant, and did not take any other wives until her death, a period of about 25 years. At the age of 40, he is believed to have received a spiritual revelation and began to propagate it in Mecca. He regarded himself as a successor of Abraham’s lineage and did not consider that he was proclaiming a new God; rather, he believed he was reaffirming the monotheistic faith already taught by Abraham.

These activities provoked opposition from Mecca's religious leaders and merchants, eventually putting him and his followers under threat. Consequently, in 622 CE, Muhammad and his followers migrated collectively to Medina, an event known as the Hijra. This migration led to the formation of the Muslim community, the Ummah, in Medina, which marks the starting year of the Islamic calendar.

Scriptures

According to Islamic tradition, God revealed scriptures to Adam, Seth, Enoch, Abraham, and others, but those scriptures were lost. Only the Torah (Tawrāt) revealed to Moses, the Psalms (Zabūr) revealed to David, the Gospel (Injīl) revealed to Jesus, and the Qur’an (Qur’ān) revealed through Muhammad are believed to have survived.

During the early Meccan period, Muhammad respected Jews and referred to them as the “People of the Book.” However, as Jews did not acknowledge him as a prophet, the relationship gradually changed. Gabriel (2002) divided these changes into three stages:

1. Stage 1 (Meccan Period, 610–623 CE): Muhammad attempted to convert Jews while emphasizing the commonalities between Jews and Christians and the continuity of revelation. Orthodox and heterodox Christians coexisted in Mecca, including the Ebionites and Nestorians. During this period, the Qur’an contains relatively many passages favorable toward Jews.

2. Stage 2 (Medinan Period, 623–632 CE): Muhammad drew a clear line with Jews who rejected him and experienced military conflicts. As Jews did not recognize his revelations and claims, the Qur’an began to include criticism and curses directed at Jews. During this period, revelations such as the so-called “Verse of the Sword” appeared, which included instructions to subdue Jews and Christians.

3. Stage 3 (After 632 CE): After subjugating the Jews, the relational distance between Muhammad and Jews and Christians intensified. These changes formed the background for biblical criticism passages and the doctrine of corruption of earlier scriptures.
   

Through this process, it became believed that scriptures prior to the Qur’an were corrupted by Jews and Christians.

In the early period after Muhammad’s death, the Qur’an was primarily transmitted through memorization. However, due to wars, many reciters died, increasing the risk of loss of the Qur’an. Therefore, the first caliph, Abu Bakr, ordered the collection of the written Qur’an, and the third caliph, Uthman, standardized the versions transmitted in various regions and destroyed the remaining copies.

The resulting standard Qur’an, which survives today, was largely arranged according to the length of surahs, rather than the chronological order of revelation. Consequently, passages favorable and critical toward Jews and Christians appear intermixed (e.g., Qur’an 3:52, 3:55, 5:49, 5:69 are relatively favorable, whereas 2:78, 2:79, 3:78, 3:79, 11:110 are critical).

Additionally, the Qur’an mentions the concepts of naskh (abrogation) and mansūkh (repeal), indicating that previous revelations can be replaced by subsequent ones (Qur’an 2:106). This characteristic complicates the interpretation and understanding of the Qur’an for ordinary readers.

Distribution and Scale

Islam is predominantly found in the Middle East, North Africa, Anatolia, the Caucasus, Persia, Southwest Asia, Central Asia, China’s Xinjiang Uyghur Autonomous Region, and Southeast Asia. Between 2010 and 2020, the global Muslim population increased by approximately 347 million, reaching roughly 2 billion (Pew Research Center, 2025).

Core Beliefs

The core of Islamic faith is summarized in six fundamental beliefs, known as al-īmān:

1. Tawḥīd (Oneness of God): Belief in the absolute oneness of God. The declaration of faith for becoming a Muslim is “There is no god but Allah,” specifically emphasized in Surah 112. Violating this principle is called Shirk and is considered an unforgivable major sin.

2. Belief in Angels: Angels are special creations of God who obey God’s will absolutely. The four major archangels are Jibrīl (Gabriel), Mīkā’īl (Michael), Izrā’īl (Angel of Death), and Isrāfīl (who blows the trumpet on Judgment Day). Additionally, angels record humans’ good and bad deeds.

3. Belief in Holy Books: God delivered scriptures through apostles and prophets. Originally, 104 scriptures existed, but today only four remain: the Torah (Tawrāt), Psalms (Zabūr), Gospel (Injīl), and Qur’an (Qur’ān).

4. Belief in Prophets: God sent prophets and apostles from the beginning to convey His will. It is believed that there were 124,000 prophets in total. The Qur’an records only 25, 21 of whom appear in the Bible. Their core message was always Tawḥīd. Prophets range from Adam to Muhammad, the last prophet, called Rasūl (Messenger) or Nabī (Prophet).

5. Belief in the Afterlife and Judgment Day: Humans are judged according to their deeds. Righteous Muslims receive pure spouses in paradise, whereas wrongdoers are punished in hell.

6. Belief in Predestination (Qadar): All human actions and existence are determined by God’s will. God knows everything, and all events occur and cease according to His will.

Islamic Practices

Islam is an action-oriented religion. Muslims practice the Five Pillars (al-arkān al-khamsa) within the framework of ʿIbādah (worship and obedience to God):

1. Shahādah (Declaration of Faith): Proclaiming faith in Allah and Muhammad: “La ilāha illallāh, Muhammadun Rasūlullāh.” This is sufficient to become a Muslim. It is recited repeatedly in the Adhān and appears on the Saudi Arabian flag.

2. Ṣalāh (Obligatory Prayer): Praying five times daily facing Mecca. Ritual purification (Wudu) precedes prayer. Prayer times are dawn, noon, late afternoon, sunset, and night. Personal supplications (Dua) may be added.

3. Zakāt (Obligatory Alms): Giving 2.5% of annual income to orphans and the poor. Distinct from voluntary charity (Sadaqah).

4. Ṣawm (Fasting): Abstaining from food, drink, and sexual activity during Ramadan from dawn to sunset. Focus is on spiritual purification, prayer, and charity. Laylat al-Qadr on the 27th night commemorates the Qur’an’s revelation.

5. Ḥajj (Pilgrimage): Visiting Mecca at least once in a lifetime. Completing the pilgrimage absolves sins. Financially constrained individuals may participate indirectly. Completed pilgrims are called Hajji.

Jihād is also included, originally referring to defending Islamic teachings through combat but now encompassing moral, intellectual, and spiritual efforts. Some consider it the sole religious practice.

Islamic Denominations

1. Sunni (Sunni, “People of the Sunnah and Community”): Comprising about 70% of Muslims, Sunnis believe that the Muslim community has correctly preserved and followed God’s teachings since Muhammad’s death. They follow the four sources of Islamic law: Qur’an (God’s revelation), Sunnah & Ḥadīth (The exemplary life of Muhammad and his recorded sayings and actions), qiyās (analogical reasoning), and ijmāʿ (consensus of the community). Sunni jurisprudence includes four main schools (madhhab): Hanafi (Abu Hanifa), Maliki (Ibn Malik), Shafi’i (Imam al-Shafi’i), and Hanbali (Ahmad ibn Hanbal). They differ in detailed legal interpretation but share common positions on essential matters.

2. Shīʿa (Shīʿa, “Followers of Ali”): Comprising 10–20% of Muslims, Shīʿa do not recognize the legitimacy of Sunni caliphs. They follow Ali, Muhammad’s cousin and son-in-law, believing that God’s true intent is not fully revealed in the Qur’an. Only Ali and his descendants, the Imams, possess special authority to understand God’s will. Main subgroups include the Twelve Imams, Ismaili, and Zaydi.

3. Sufism (Sufism, Islamic Mysticism): The term “Sufi” derives from sūf, meaning wool, as early practitioners wore wool garments symbolizing asceticism and poverty. Sufism emphasizes spiritual practice and experience over doctrinal or legal observance. Sufi orders (ṭarīqa) include Qādiriyya, Naqshbandiyya, Mevleviyya, and Bektāshiyya.

Coexistence and Conflict with Christianity

Ancient Persia, unlike the Assyrian and Babylonian empires, allowed the return of conquered peoples and religious tolerance, establishing a multicultural policy. This tradition was inherited by the Arab and Ottoman empires. The Arabs developed the Dhimmi system, and the Ottomans the Millet system, managing non-Muslim communities institutionally (Qur’an 2:256). Dhimmi means “protected people.” The system required non-Muslims to pay the jizya (poll tax) and kharaj (land tax) in exchange for protection. The Millet system institutionalized Dhimmi autonomy within the administrative structure. Prominent Ottoman millets included Muslims, Greek Orthodox, Armenians, and Jews. Thus, Judaism and Christianity continued to exist in Islamic-majority regions of the Middle East and North Africa. While local conflicts occurred over time, overall governance allowed coexistence.

However, this coexistence was disrupted by the rise of global terrorism following the September 11 attacks in 2011. Global terrorism is not a temporary phenomenon but a well-structured theological and activist alternative movement within the Islamic world, which continues despite international sanctions.

References

Gabriel, M. A. (2002). Islam and terrorism. FrontLine.

Pew Research Center. (2025, June 10). Islam was the world’s fastest-growing religion from 2010 to 2020. https://www.pewresearch.org/short-reads/2025/06/10/islam-was-the-worlds-fastest-growing-religion-from-2010-to-2020/