Islam (; , ) is an Abrahamic monotheistic religion. All of its teachings and beliefs are written out in the Quran (also spelled Qur'an or Koran), the holy scripture of Islam. Believers of Islam are called Muslims which means "submitter to God". They believe that the Quran was spoken to Muhammad by the angel Gabriel, and that it is the word of God (or Allah). They view Muhammad as a prophet and messenger of God. Other beliefs and rules about what Muslims should do come from reports of what Muhammad taught or "hadith".