The Muslim faith, also known as Islam, is a monotheistic religion based on the teachings of the prophet Muhammad. It is one of the world's largest religions, with over 1.8 billion adherents worldwide. The core beliefs of Islam include belief in one God, the prophets, and the holy books. Muslims also believe in angels, predestination, and the Day of Judgment. Islamic law, or Sharia, governs many aspects of daily life, including marriage, divorce, inheritance, and criminal justice.