Beginning in Jerusalem on the day of Pentecost, the Christian faith spread by preaching the good news of salvation in Jesus Christ. The book of Acts tells how despite persecutions, the first Christians “preached the word wherever they went” (8:4). The early centuries of Islam followed a much different pattern. Already during the lifetime of Muhammad, his religion spread by the sword. At the time of his death, the prophet was ruler over most of Arabia. That pattern of conquest did not stop with his passing.
Spread of Islam under the Rightly Guided Caliphs
The early and formative history of Islam revolves around the first four successors of Muhammad, all of whom ruled from the city of Medina in Arabia.