Islam is a religion.
Islam . الإسلام , [ alʔisˈlaːm ] ) is an Abrahamic monotheistic religion which professes that there is only one and incomparable God ( Allah ) and that Muhammad is the last messenger of God . It is the world 's second-largest religion and the fastest-growing major religion in the world , with over 1.8 billion followers or 24.1 % of the global population , known as Muslims . Like other Abrahamic religions , Islam also teaches a final judgment with the righteous rewarded paradise and unrighteous are punished in hell .