Short answer
- Islam is a monotheistic Abrahamic religion based on the Quran and the teachings of the Prophet Muhammad. The Arabic word islam means "surrender," and a Muslim is someone who surrenders to the will of God (Allah). Muslims believe in one God, hold Muhammad to be the last of a line of prophets that includes Adam, Abraham, Moses, and Jesus, and practice five core duties known as the Five Pillars. About 1.8 billion people as of 2015, roughly 24% of the world's population, identify as Muslim, making Islam the world's second-largest religion after Christianity, according to Pew Research Center estimates.
Islam shapes the daily lives of nearly a quarter of humanity, yet many people outside the faith encounter it only through headlines. This article explains what the religion actually teaches, how it began, what Muslims do in practice, and where its two main branches came from, drawing on encyclopedia entries, demographic research, and academic biographies rather than slogans from any side.
Where the phrase “Islam is the religion” comes from
The keyword behind this article is a phrase, not just a topic. The Quranic Arabic Corpus records that the word Islam appears in verse 3:19 of the Quran, which the Sahih International translation renders: “Indeed, the religion in the sight of Allah is Islam.” That verse is one reason the exact phrase “Islam is the religion” appears in English-language searches. It reflects the Muslim belief that Islam is the complete and final expression of a single original faith revealed through earlier prophets. This article treats the phrase as its doorway into the broader question: what is Islam, and what do its followers believe?
What the word “Islam” means
The Arabic term islam literally means “surrender,” as Encyclopaedia Britannica explains, and it illuminates the central religious idea of the faith: the believer accepts surrender to the will of Allah, the Arabic word for God. A Muslim is, in the literal sense, “one who surrenders.” Muslims view Allah as the sole God, creator, sustainer, and restorer of the world. The religion is uncompromisingly monotheistic: there are no partners, offspring, or equals alongside God, a doctrine known as tawhid, the oneness and uniqueness of God.
The core beliefs of Islam
Islamic belief is often summarized in six articles of faith, which Muslims hold as matters of doctrine:
- Belief in one God. Absolute monotheism is the foundation. The Quran’s central message, Britannica notes, is the absolute oneness of God.
- Belief in angels. Muslims believe God created angels as obedient servants who carry out divine commands. The archangel Gabriel is the one believed to have delivered the Quran to Muhammad.
- Belief in the prophets. Muslims believe God guided humanity through a line of prophets, including Adam, Noah, Abraham, Moses, Solomon, and Jesus, with Muhammad as the last. His message is understood to confirm and complete the revelations given to earlier prophets.
- Belief in the scriptures. Muslims accept the Quran as God’s final and unaltered word, and also affirm the earlier revelations, such as the Torah (Tawrat), the Psalms (Zabur), and the Gospel (Injil), as originally given.
- Belief in the Day of Judgment. Muslims believe that after death, the righteous will be rewarded in paradise and the unrighteous punished, and that believers should live in preparation for that day.
- Belief in divine decree. Muslims believe that God is all-knowing and that all things occur within God’s knowledge and will, while human beings remain responsible for their choices.
These beliefs are shared across the religion’s branches, even where practices and interpretations differ.
The Quran
The Quran (literally “reading” or “recitation”) is the holy scripture of Islam, believed by Muslims to be the direct, verbatim word of God delivered to Muhammad by the archangel Gabriel between 610 and 632 CE. The word itself highlights the text’s importance as an oral scripture: its verses are recited in daily prayers, memorized by millions, and studied for guidance on matters ranging from worship to social conduct.
The Quran is divided into 114 suras (chapters) of unequal length. The suras revealed at Mecca during the earliest part of Muhammad’s career focus mostly on ethical and spiritual teachings and the Day of Judgment, while those revealed later at Medina deal more with social legislation and the principles for ordering the community.
Alongside the Quran, Muslims rely on the Sunnah, the example of the Prophet, meaning his words and deeds as recorded in compilations called Hadith (literally “report”). Six of these Hadith collections, compiled in the 9th century CE, came to be regarded as especially authoritative by Sunni Muslims, while Shia Muslims have their own Hadith in four canonical collections. Islamic doctrine, law, and thought in general rest on four foundational sources: the Quran, the Sunnah, ijma (scholarly consensus), and ijtihad (independent reasoning).
The Prophet Muhammad
Muslims consider Muhammad the final prophet in a line that includes Adam, Noah, Abraham, Moses, and Jesus. Through him, they believe, God revealed the complete message of the Quran. Britannica’s account places his activity in 7th-century Arabia: he began preaching in Mecca, where his small group of followers faced persecution, and in 622 CE he migrated to Medina, an event called the Hijra that marks the beginning of the Islamic calendar. In Medina his preaching was soon accepted, and the community-state of Islam emerged. Within a century after the Prophet’s death in 632 CE, Muslim armies and administrators had brought a large part of the globe, from Spain across Central Asia to India, under a new Arab Muslim empire.
Islam teaches strict monotheism, so Muhammad is not worshipped; he is revered as God’s messenger and as the model of how a Muslim should live. His actions and sayings, preserved in the Hadith, serve as a guide for Muslims second only to the Quran.
The Five Pillars of Islam
The Five Pillars are the core duties of Islam, incumbent on every Muslim. They are:
1. Shahada: the profession of faith
“There is no god but God; Muhammad is the Prophet of God.” This declaration must be recited aloud, correctly, and with understanding at least once in a lifetime. It is the statement by which a person enters the Muslim community, and it sums up the two foundations of the faith: monotheism and Muhammad’s prophethood.
2. Salat: the daily prayers
Muslims perform ritual prayer five times each day: at dawn (fajr), midday (dhuhr), afternoon (asr), sunset (maghrib), and evening (isha). Each prayer follows a prescribed sequence of recitations from the Quran and physical postures, and is performed facing the Kaaba in Mecca. Muslims may pray individually in any clean space or together in a mosque, where the prayer is led by an imam. Friday midday prayers include a sermon and hold special communal importance. Illness, travel, or danger allow for modifications or postponement.
3. Zakat: almsgiving
Zakat is an obligatory alms tax levied for the benefit of the poor and needy. It expresses the belief that wealth is a trust from God and that a portion of it belongs by right to those in need. Beyond the formal obligation, voluntary charity is strongly encouraged.
4. Sawm: fasting during Ramadan
During Ramadan, the ninth month of the Islamic calendar, Muslims abstain from food and drink from daybreak to sunset. The fast is a discipline of self-restraint and empathy with the hungry, and the month is also devoted to extra prayer, Quran reading, and community gatherings. Those who are ill, traveling, pregnant, or otherwise unable to fast are exempt or make up the days later.
5. Hajj: the pilgrimage to Mecca
The hajj is the major pilgrimage to Mecca in Saudi Arabia, which every adult Muslim must make at least once in a lifetime if physically and financially able. Pilgrims perform a series of rites over several days, including circling the Kaaba, standing in prayer on the plain of Arafat, and symbolic acts retracing the stories of Abraham. The pilgrimage draws millions of people each year and is one of the largest regular human gatherings on earth.
Sunni and Shia: the two main branches
Sunnis and Shias are the two main branches of Islam, and the divide between them is nearly 1,400 years old. It dates to a dispute over the succession of leadership in the Muslim community following the death of the Prophet Muhammad in 632, as Pew Research Center explains. The two groups agree on the core tenets of Islam, including the oneness of God, the prophethood of Muhammad, and the authority of the Quran, but they differ on questions of religious leadership and, over the centuries, on law and practice.
Sunnis form the overwhelming majority. Pew Research Center estimates that 87 to 90 percent of the world’s Muslims are Sunni. The name comes from ahl al-sunnah, “the people of the Sunnah,” referring to following the practices of Muhammad. After Muhammad’s death, the majority of the community accepted the selection of Abu Bakr, a close companion of the Prophet, as the first caliph (successor and leader). Sunnis recognize the first four caliphs, Abu Bakr, Umar, Uthman, and Ali, as the “rightly guided” caliphs.
Shias make up an estimated 10 to 13 percent of Muslims worldwide, according to Pew. The name is short for Shiat Ali, “the party of Ali.” Shias hold that leadership of the Muslim community should have remained within Muhammad’s family, specifically with his cousin and son-in-law Ali, whom they regard as the first Imam, a divinely guided leader, after the Prophet. Ali did become the fourth caliph in 656 CE, but his reign was marked by civil war, and he was assassinated in 661 CE, after which the Umayyad caliphate was established in Damascus. Shia Islam developed distinct traditions around the Imams, beginning with Ali, and today includes major groups such as the Twelvers (the largest), Ismailis, and Zaidis.
It is worth noting that in some countries, including several in Central Asia and Southern and Eastern Europe, large numbers of Muslims identify simply as “just a Muslim” rather than with either branch, Pew’s surveys found. Within Sunni Islam there are also several schools of jurisprudence that interpret religious law differently, and within Shia Islam there are distinct traditions as well. Theological disputes between the branches are real and long-standing, and this article describes each side’s position without taking one.
A short history of Islam
Islam began with Muhammad’s preaching in Mecca in the early 7th century. After the Hijra to Medina in 622 CE, the Muslim community grew into a political as well as religious force. The early caliphs who succeeded Muhammad oversaw rapid expansion: within a century of his death, Muslim rule stretched from Spain to India.
The first centuries also saw the formation of Islamic law, theology, and scholarship. After the early caliphates, power passed through the Umayyad dynasty (based in Damascus) and then the Abbasid dynasty (based in Baghdad), under whom cities like Baghdad, Cordoba, and Cairo became centers of science, medicine, mathematics, philosophy, and art. This period is often called the Islamic Golden Age.
Later centuries brought the Ottoman Empire, which at its height controlled much of Southeast Europe, the Middle East, and North Africa, as well as the Safavid Empire in Persia and the Mughal Empire in India. A second, quieter wave of expansion had already carried the faith far beyond the reach of armies: after the 12th century, Sufi mystics were mainly responsible for spreading Islam in India, Central Asia, Turkey, and sub-Saharan Africa, while Muslim traders carried it to Indonesia, Malaya, and China. Britannica notes that Islam was introduced to Indonesia in the 14th century, and Indonesia is today the country with the world’s largest Muslim population.
European colonialism in the 19th and 20th centuries redrew the political map of Muslim-majority regions, and the mid-20th century saw most of them gain independence. In the modern era, Muslims live in nearly every country, and the religion continues to grow, chiefly for demographic reasons.
Islam around the world today
Pew Research Center estimated that there were 1.8 billion Muslims in the world as of 2015, roughly 24 percent of the global population, making Islam the world’s second-largest religion after Christianity and the fastest-growing major religion. Pew projects that if current trends continue, the Muslim population will reach nearly 3 billion by 2060, about 31 percent of humanity, and could exceed the number of Christians by the end of this century. Two demographic facts drive the growth: Muslim women have more children on average than women of other religious groups (about 2.9 children each), and Muslims have the youngest median age of any major religious group (24 in 2015).
Although the religion originated in the Middle East and North Africa, that region is home to only about 20 percent of the world’s Muslims. A majority, 62 percent, live in the Asia-Pacific region, including large populations in Indonesia, India, Pakistan, Bangladesh, Iran, and Turkey. Indonesia currently has the world’s largest Muslim population, though Pew projects India will hold that distinction by 2050. Muslim populations are also growing in Europe and North America through immigration and higher birth rates; Pew estimated about 3.45 million Muslims in the United States as of 2017, around 1.1 percent of the U.S. population.
Holy days and the Islamic calendar
Islam follows a lunar calendar of 354 or 355 days, so its holy days move about 11 days earlier each year relative to the solar calendar. The two most important festivals are:
- Eid al-Fitr, the “Festival of Breaking the Fast,” marks the end of Ramadan. It is a joyous celebration with communal prayer, special foods, gifts, and visits with family and friends.
- Eid al-Adha, the “Festival of Sacrifice,” commemorates Abraham’s willingness to sacrifice his son in obedience to God. Families who can afford it sacrifice an animal and share the meat with relatives and the poor. It coincides with the annual hajj pilgrimage.
Ramadan itself, the ninth month, is the holiest month of the year, devoted to fasting, prayer, and reflection. The Night of Decree (Laylat al-Qadr), believed to be the night on which the first verses of the Quran were revealed, falls within its last ten days and is considered the holiest night of the year.
Worship, holy places, and daily practice
The mosque is the Muslim place of worship and community gathering. Its most distinctive features often include a prayer hall oriented toward Mecca, a minaret (tower) from which the call to prayer is announced, and a mihrab (niche) indicating the direction of prayer, the qibla.
Three sites hold special holiness in Islam: the Masjid al-Haram in Mecca, home of the Kaaba, the cube-shaped structure draped in black cloth toward which Muslims pray; the Prophet’s Mosque in Medina, where Muhammad is buried; and the al-Aqsa Mosque compound in Jerusalem.
Daily practice extends beyond the Five Pillars. Halal dietary rules prohibit pork and alcohol, and require meat to be slaughtered in a prescribed manner. Dress customs vary enormously by culture and personal conviction: many Muslim women cover their hair with a hijab, while practices differ widely across regions, and many Muslim men and women dress in no visibly distinctive way at all. Honesty in trade, care for parents and neighbors, and regular charity are emphasized throughout Islamic teaching.
Islam and the other Abrahamic faiths
Islam counts itself among the Abrahamic religions, alongside Judaism and Christianity, and Muslims believe their faith completes a single line of revelation. Jesus holds a special place in Islam: Muslims revere him as a prophet and the Messiah, believe in his miraculous virgin birth to Mary (who is honored in the Quran with an entire chapter named for her), but do not believe he was divine or was crucified in the manner Christians affirm. The Quran describes God raising Jesus to himself.
In early Islamic history, Jews and Christians were assigned a special status as “people of the Book” (ahl al-kitab), communities possessing earlier scriptures, and were generally allowed religious autonomy in exchange for a per capita tax called the jizyah, while pagans were required to either accept Islam or die. Over the centuries, relations between the faiths have included both cooperation and conflict, and modern interfaith dialogue continues in many countries.
Questions people often ask
Does “Islam” mean “peace”? The word islam shares the Arabic root s-l-m with the word salam (peace), and Muslims often greet one another with “peace be upon you.” But the word itself, as Britannica explains, literally means “surrender,” referring to surrender to God’s will. Describing Islam simply as “the religion of peace” is a slogan, not a translation.
What is jihad? Britannica renders jihad as “exertion” and notes it is commonly translated as “holy war” or “holy struggle,” but that in the Quran the term has multiple meanings. In Islamic tradition it most often refers to the spiritual struggle to live righteously, though it has also been used historically to mean armed struggle, and extremist groups have invoked it to justify violence. The overwhelming majority of Muslims reject that violent interpretation: Pew’s surveys found that in most countries with large Muslim populations, most Muslims say suicide bombings and violence against civilians are rarely or never justified.
What is sharia? Sharia is Islamic law, derived from the Quran and the Sunnah, covering worship, family life, finance, and ethics. Attitudes toward it vary widely: a Pew survey across 39 countries found that nearly all Muslims in Afghanistan (99%) want sharia to be the official law of the land, while in countries like Turkey (12%), Kazakhstan (10%), and Azerbaijan (8%), relatively few do. How sharia is interpreted and applied differs by school of thought and country.
Do Muslims and Christians worship the same God? Muslims and Christians both profess one God, and “Allah” is simply the Arabic word for God, used by Arabic-speaking Christians as well. Whether the two faiths’ understandings of God are the same is a theological question on which believers differ, and this article does not adjudicate it.
Frequently asked questions
What is the difference between Islam and Muslim? Islam is the religion; a Muslim is a person who follows it. The word “Muslim” literally means “one who surrenders” to God.
Who founded Islam? Muslims do not describe Muhammad as the “founder” in the ordinary sense. They believe Islam is the original faith of humanity, revealed through many prophets, with Muhammad as the final prophet who completed it in 7th-century Arabia.
What do Muslims believe about the afterlife? Muslims believe in a Day of Judgment on which the righteous will be rewarded in paradise (jannah) and the unrighteous punished in hell (jahannam), and they believe earthly life should be lived in preparation for it.
Why do Muslims pray facing Mecca? Muslims pray facing the Kaaba in Mecca, Islam’s holiest site, as a sign of unity: wherever they are in the world, all Muslims orient themselves toward the same point.
What is the Quran’s view of earlier scriptures? Muslims believe the Torah, Psalms, and Gospel were genuine revelations from God in their original form, and they believe the Quran confirms and completes them as the final, preserved revelation.
How is Islam different from Christianity and Judaism? All three are Abrahamic monotheistic faiths. Islam’s distinctive claims are the finality of Muhammad’s prophethood, the Quran as God’s literal and final word, and strict monotheism without a Trinity or divine sonship. Each faith understands these differences in its own way.
Keep reading: How Many Countries Are There in the World?
Sources & references
- Encyclopaedia Britannica, "Islam," including the article's Top Questions/FAQ section.
- Pew Research Center, "Muslims and Islam: Key findings in the U.S. and around the world" (9 Aug 2017).
- Pew Research Center, "Sunni and Shia Muslims" (from The Future of the Global Muslim Population, 2011).
- Pew Research Center, "Mapping the Global Muslim Population" (7 Oct 2009). Figures cited via the Pew page.
- EBSCO Research Starters, "Ali ibn Abi Talib" biography.
- Quranic Arabic Corpus, Ontology of Quranic Concepts: "Islam" (verse 3:19, Sahih International translation).
- Wikipedia, "Islam" and "Ali" articles: used only as supporting sources for terminology (tawhid, holiest sites) and minor dates, flagged as qualified in the writer ledger.
