The core beliefs of Islam are that there is only one God—unitary and beyond comprehension—and that Muhammad is his prophet, the last in a series beginning with Adam and including Noah, Abraham, Moses, and Jesus. The Qur’an is upheld as the eternal, literal word of God, and revelations to earlier prophets, as portrayed in the Jewish and Christian scriptures, are considered distorted by human intervention. Muslims believe that the Qur’an was revealed to Muhammad through the angel Gabriel; angels as God’s servants are part of the Islamic tradition. Belief in the “Day of Judgment,” when all people will undergo bodily resurrection and judgment by God, is another core tenet. While Sunni and Shi’a Muslims adhere to these basic beliefs, Shi’a also believe in the Imamate, the line of infallible spiritual and political leaders who succeeded Muhammad, beginning with his cousin and son-in-law, Ali.