Islam is an Abrahamic, monotheistic religion which teachings and beliefs are that there is only one God and Muhammad is the messenger of God. It is the world's second-largest religion with over 1.8 billion followers or 24.1% of the world's population, commonly known as Muslims. Muslims believe that Islam is the complete and universal version of a primordial faith that was revealed many times before through prophets including Adam, Abraham, Moses and Jesus, and the Quran in its Arabic to be the unaltered and final revelation of God.