Muhammad was the Prophet who revealed God 's will in all of life 's concerns .
Belief in Islam entailed both loyalty to a chief whose authority derived from his religious position , and membership in the umma - the community he led .
Since Muhammad was the Prophet who revealed God 's will in all of life 's concerns , belief in Islam entailed both loyalty to a chief whose authority derived from his religious position , and membership in the umma - the community he led .