Islam is an Abrahamic religion based on the Quran and the teachings of Muhammad. The monotheistic religion has an estimated 2 billion worldwide adherents, called Muslims. Islam is the world's second-largest religion, after Christianity. Muslims believe that the primordial faith was revealed many times through successive prophets and messengers, including Adam, Noah, Abraham, Moses, and Jesus, and that Islam is the universal and complete form of this faith.
It teaches that God is one, merciful, omnipotent, without equal, and that he has guided humanity through various prophets, scriptures, and natural signs. Muslims consider the Quran to be the verbatim word of God and the unaltered, universal, final revelation. Alongside the Quran, Muslims also believe in previous revelations, including the Tawrat (Torah), the Zabur (Psalms), and the Injil (Gospel). They believe that Muhammad is the Seal of the Prophets and final prophet of God, through whom the religion was completed, and after whom no new prophet or divine law will come. The teachings and normative examples of Muhammad (Sunnah), documented in accounts called Hadith, provide a constitutional model for Muslims. Islam is based on the uniqueness of God (Tawhid), and belief in the afterlife (Akhirah) with the Last Judgment—wherein the righteous will be rewarded in paradise (Jannah) and the unrighteous will be punished in hell (Jahannam). The Five Pillars, considered obligatory acts of worship, are the profession of faith (Shahada), daily prayers (Salah), almsgiving (Zakat), fasting in the month of Ramadan (Sawm), and a pilgrimage to Mecca (Hajj). Islamic law (Sharia) touches on virtually every aspect of life, from banking and finance and welfare to men's roles and women's roles and the environment. The two main religious festivals are Eid al-Fitr and Eid al-Adha. The three holiest sites are Masjid al-Haram in Mecca, the Prophet's Mosque in Medina, and Al-Aqsa Mosque Compound in Jerusalem.
Islam originated in Mecca c. 610 CE, when Muslims believe that Muhammad received his first revelation through Gabriel. By the time of his death, most of the Arabian Peninsula had converted to Islam. Islam rapidly expanded beyond Arabia under the Rashidun and Umayyad Caliphates. The two Islamic branches are Sunni Islam (87–90%) and Shia Islam (10–13%). Sunni and Shia Muslims together constitute nearly the entire global Muslim population, with estimates ranging from approximately 1.7–1.8 billion Sunnis to 285–300 million Shias worldwide. The Shia–Sunni schism initially arose from disagreements over the succession to Muhammad, and grew to encompass broader differences over the centuries, including distinct theological traditions, schools of jurisprudence, religious practices, and collections of hadith. Nevertheless, both branches share the fundamental foundations of Islam. The Sunni canonical hadith collection consists of The Six Books, while the Shia canonical hadith collection consists of The Four Books. Muslims are the world's fastest-growing major religious group, primarily due to a higher fertility rate and younger age structure compared to other major religions. It is projected that by 2050, the number of Muslims worldwide will equal the number of Christians, and Islam will become the world's largest religion by the end of the 21st century, surpassing Christianity.
In Arabic, Islam (Arabic: إسلام, lit. 'submission [to God]') is the verbal noun of Form IV originating from the verb سلم (salama), from the triliteral root س-ل-م (S-L-M), which forms a large class of words mostly relating to concepts of submission, safeness, and peace. In a religious context, it refers to the total surrender to the will of God. A Muslim (مُسْلِم), the word for a follower of Islam, is the active participle of the same verb form, and means "submitter (to God)" or "one who surrenders (to God)". However, Quranic studies scholar Mohsen Goudarzi has argued that in the Quran the word dīn means "worship", the islām means "monotheism" and the muslim means "monotheist". In the Hadith of Gabriel, Islam is presented as one part of a triad that also includes imān (faith), and ihsān (excellence). Islam itself was historically called Mohammedanism in the English-speaking world. This term has fallen out of use and is sometimes said to be offensive, as it suggests that a human being, rather than God, is central to Muslims' religion.
The Islamic creed (aqidah) requires belief in six articles: God, angels, revelation, prophets, the Day of Resurrection, and the divine predestination.
The central concept of Islam is tawḥīd (Arabic: توحيد), the oneness of God. It is usually thought of as a precise monotheism, but is also panentheistic in Islamic mystical teachings. God is seen as incomparable and without multiplicity of persons such as in the Christian Trinity, and associating multiplicity to God or attributing God's attributes to others is seen as idolatry, called shirk. Thus, Muslims are not iconodules and do not attribute forms to God. God is instead described and referred to by several names or attributes, the most common being Ar-Rahmān (الرحمان) meaning "The Entirely Merciful", and Ar-Rahīm (الرحيم) meaning "The Especially Merciful" which are invoked at the beginning of most chapters of the Quran. The direct Arabic name for God, Allāh (الله), a term with no plural or gender, is also commonly used in other languages by Muslims and Arabic-speaking Christians and Jews to refer to God, whereas ʾilāh (إله) is a term used for a deity or a god in general. Islam teaches that the creation of everything in the universe was brought into being by God's command as expressed by the wording, "Be, and it is," and that the purpose of existence is to worship God. He is viewed as a personal god and no intermediaries, such as clergy, are needed to enable contact with God. Awareness of God is referred to as taqwa.
Angels (singular: Arabic: ملك, malak) are beings described in the Quran and hadith. They are described as created to worship God and also to serve in other specific duties such as communicating revelations from God, recording every person's actions, and taking a person's soul at the time of death. They are described as being created variously from 'light' (nūr) or 'fire' (nār). Islamic angels are often represented in anthropomorphic forms combined with supernatural images, such as wings, being of great size or wearing heavenly articles. Common characteristics for angels include a lack of bodily needs and desires, such as eating and drinking. Some of them, such as Gabriel (Jibrīl) and Michael (Mika'il), are mentioned by name in the Quran. Angels play a significant role in literature about the Mi'raj, where Muhammad encounters several angels during his journey through the heavens. Further angels have often been featured in Islamic eschatology, theology and philosophy.
The pre-eminent holy text of Islam is the Quran. Muslims believe that the verses of the Quran were revealed to Muhammad by God, through the archangel Gabriel, on multiple occasions between 610 CE and 632, the year Muhammad died. While Muhammad was alive, these revelations were written down by his companions, although the primary method of transmission was orally through memorization. The Quran is divided into 114 chapters (sūrah) which contain a combined 6,236 verses (āyāt). The chronologically earlier chapters, revealed at Mecca, are concerned primarily with spiritual topics, while the later Medinan chapters discuss more social and legal issues relevant to the Muslim community.
Muslim jurists consult the hadith ('accounts'), or the written record of Muhammad's life, to both supplement the Quran and assist with its interpretation. The science of Quranic commentary and exegesis is known as tafsir. In addition to its religious significance, the Quran is widely regarded as the finest work in Arabic literature, and has influenced art and the Arabic language. Islam also holds that God has sent revelations, called wahy, to different prophets numerous times throughout history. However, Islam teaches that parts of the previously revealed scriptures, such as the Tawrat (Torah) and the Injil (Gospel), have become distorted—either in interpretation, in text, or both, while the Quran (lit. 'Recitation') is viewed as the final, verbatim and unaltered word of God.