All Muslims must believe in God, his angels, his revelations, and his messengers.

God revealed his final message through the prophet Muhammed.

2:177] Righteousness is not turning your faces towards the east or the west. Righteous are those who believe in GOD, the Last Day, the angels, the scripture, and the prophets; and they give the money, cheerfully, to the relatives, the orphans, the needy, the traveling alien, the beggars, and to free the slaves; and they observe the Contact Prayers (Salat) and give the obligatory charity (Zakat); and they keep their word whenever they make a promise; and they steadfastly persevere in the face of persecution, hardship, and war. These are the truthful; these are the righteous.