Who were the first practicing muslims, and why was Muhammad both their religious and political leader?

Muhammad was a political leader because he was a leader of the state, and he was a religious leader because he was a prophet of the lord according to Islamic beliefs. He received numerous instructions from god through the angel Gabriel, known in Islam as Jibril, and based on these rules and guidelines the Quran was created. People who were Muslims before Muhammad also accepted that it was a religion based on having prophets of the lord such as Abraham, Noah, Jesus, and others, but the stories slightly differed, with Muhammad being the final prophet that this world has seen.