He was the last Prophet of Islam. He was commanded by Almighty Allah Karim to preach in public.
the main teaching prophet was to preach islam
he did them in quiet meetings. after three years he called ISLAM in public
he was a prophet and a messenger. his duty was to bring in new followers and preach the teachings of allah
Any Muslim scholar having true knowledge of Islam can preach Islam. In a way, anybody can preach speaking truth, being honest in one's dealings, being helful to humans, being charitable and kind to all. All human beings are the Family of God. No particular kind of preacher is obligatory in Islam.
Hegira started in 622 AD and when Muhammad had to move from Mecca to Medina to preach Islam.
Malcolm X preached at Nation of Islam Temple No.7 in Harlem New York
When He was younger, he worked as a shephard but later as a merchant, until he received the call to Prophethood for which he left everything and began to preach Islam.
Islam is the continuation of Judaism and Christianity. Hazrat Muhammad (SAW) is the last prophet of Islam. Like all the heavenly religions, Islam believes in ONENESS of Almighty Allah (God). Hazrat Muhammad (SAW) was ordained by Almighty Allah through Arch Angel Gabriel to preach the beliefs of Islam.
Holy Prophet Hazrat Nuh AS preached Isam and the message of Almighty Allah for nearly 950 years.
In the early days of the Nation of Islam, leaders taught that dark-skinned people were made by God, but the white people were made by a mad scientist. In recent years, they've tended to soft-peddle this aspect of their faith. __________________________________________________________ It must be recognized that no relation between Nation of Islam (NOI) and main stream Islam. True Islam forbids racism and/or discrimination. Refer to question below for details.
ISIS is an Extremist Islamic Caliphate which fights for the 'purity' of Islam. Anyone who doesn't believe in Islamic traditions/beliefs in the way they perceive it are seen as enemies. Many people devoted to Islam are disgusted by what IS are trying to achieve as what they preach is nothing but hate.