Hearing of Muhammad’s impressive credentials, Khadijah, a rich merchant widow, asked Muhammad to take some merchandise for trade to Syria. Soon after this trip when he was twenty-five, Khadijah proposed marriage to Muhammad through a relative. Muhammad accepted the proposal. At that time, Khadijah was twice widowed and forty years old. Khadijah and Muhammad were the parents of six children - four daughters and two sons. His first son Qasim died at the age of two. His second son Abdullah died in infancy. The four daughters were: Zainab, Ruqayyah, Umm Kulthum, and Fatimah.
Muhammad was forty when, during his one of many retreats to Mount Hira for meditation during the month of Ramadan, he received the first revelation from the Archangel Jibril.
On this first appearance, Gabriel said to Muhammad: "Iqraa," meaning Read or Recite. Muhammad replied, "I cannot read," as he had not received any formal education and did not know how to read or write. The Angel Gabriel then repeated what he said previously. Muhammad’s answer was the same as before. Gabriel repeated the embrace for the third time and asked him to repeat after him and said:
"Recite in the name of your Lord who created! He created man from that which clings. Recite; and thy Lord is most Bountiful, He who has taught by the pen, taught man what he knew not."
These revelations are the first five verses of chapter 96 of the Qur’an. In the year 610 CE, the revelation began. He then added that Muhammad is the expected Prophet. Khadijah accepted the revelation as truth and was the first person to accept Islam. But it was hard to prove to everyone else. She then died at the age of sixty-five in the month of Ramadan. After Khadijah's death in 620 CE, the Prophet married a widowed Muslim woman, Sawdah who was fifty years old.
Gabriel gave Muhammad a mission to restore the worship of the One True God, the creator and sustainer of the universe. In the first three years of his mission forty people accepted Islam.
At the end of his mission, the Prophet was blessed with several hundred thousand followers of Islam. Thousands prayed with him at the mosque and listened to his sermon.