Islam (/ˈɪslɑːm/;[note 1] Arabic: الإسلام, al-ʾIslām IPA: [ælʔɪsˈlæːm] ( listen)[note 2]) is a monotheistic and Abrahamic religion articulated by the Qur'an, a book considered by its adherents to be the verbatim word of God (Arabic: الله Allāh) and by the teachings and normative example (called the Sunnah and composed of Hadith) of Muhammad, considered by them to be the last prophet of God. An adherent of Islam is called a Muslim.
Muslims believe that God is one and incomparable and the purpose of existence is to love and serve God. Muslims also believe that Islam is the complete and universal version of a primordial faith that was revealed at many times and places before, including through Abraham, Moses and Jesus, whom they consider prophets. They maintain that the previous messages and revelations have been partially misinterpreted or altered over time, but consider the Arabic Qur'an to be both the unaltered and the final revelation of God. Religious concepts and practices include the five pillars of Islam, which are basic concepts and obligatory acts of worship, and following Islamic law, which touches on virtually every aspect of life and society, providing guidance on multifarious topics from banking and welfare, to warfare and the environment.
Most Muslims are of two denominations, Sunni (75–90%), or Shia (10–20%). About 13% of Muslims live in Indonesia, the largest Muslim-majority country, 25% in South Asia, 20% in the Middle East, and 15% in Sub-saharan Africa. Sizable minorities are also found in Europe, China, Russia, and the Americas. Converts and immigrant communities are found in almost every part of the world (see Islam by country). With about 1.57 billion followers or 23% of earth's population, Islam is the second-largest religion and one of the fastest-growing religions in the world.