Final answer:
Muhammad is revered in Islam as the final prophet in a lineage that includes biblical figures such as Abraham and Jesus. He received revelations from the angel Gabriel and established Islam's foundational teachings, which emphasized the worship of one God, Allah. Muslims recognize Muhammad's authority and legitimacy through the profession of faith known as the shahada.
Step-by-step explanation:
Muhammad's Authority and Legitimacy as God's Prophet:
According to Islamic teachings, Muhammad is recognized as the last in a line of prophets that includes Abraham, Moses, and Jesus, who are all revered figures in Islam. Muhammad is seen as having delivered the "definitive version" of God's will, which was revealed to him by the angel Gabriel on a mountainside. As part of embracing Islam, adherents must profess the shahada, the first of the Five Pillars of Islam, acknowledging that "There is no god but Allah, and Muhammad is the messenger of God."
In 610 CE, Muhammad received his initial revelations in a cave near Mecca, messages which emphasized the oneness of God and condemned the idol worship and greed prevalent in Meccan society. Despite the potential personal cost, Muhammad forsook his comfortable life to take up the mantle of a prophet and preacher. The Quran, along with anecdotes from the hadiths, form the basis of knowledge about Muhammad's life and teachings.
After initially facing opposition in Mecca, Muhammad and his followers migrated to Medina in an event known as the hejira, which marks the start of the Islamic calendar. In Medina, he established a religious community governed by Islamic principles, with no distinction between religious and political authority. The religion of Islam rapidly expanded during and after Muhammad's lifetime, and today it is a major world religion with followers known as Muslims, who honor Muhammad as God's final prophet.