Khadija, the daughter of Khuwaylid, was a resident of Makkah. She also belonged to the tribe of Quraysh. She was held in high esteem by the Makkans because of her exemplary character and her organizing ability.
Just as the Makkans called Muhammad ‘Sadiq' and ‘Ameen,' they called Khadija Tahira, which means “the pure one.” She was also known among the Arabs as the ‘Princess of the Merchants.' Whenever the caravans left Makkah or returned to Makkah, they noted that her cargo was larger in volume than the cargo of all other merchants of Makkah put together.
When Muhammad was 25 years old, his uncle and guardian, Abu Talib, suggested to Khadija, with his tacit understanding, that she appoint him as her agent in one of her caravans, which was ready to leave for Syria just then.
Khadija was in fact in need of an agent at that very moment. She agreed andappointed Muhammad as her agent. He took charge of her merchandise, and the caravan set out for Syria. Her slave, Maysara, also accompanied him and served him as an aide.
This commercial expedition to Syria was successful beyond expectations, and Khadija was so impressed by her agent's ability and integrity that she decided to put him in charge of all her future business transactions. The expedition also proved to be the prelude of their marriage.
Edward Gibbon
At home and abroad, in peace and war, Abu Talib, the most respected of Mohammed's uncles, was the guide and guardian of his youth; in his 25th year he entered into the service of Khadija, rich and noble widow of Mecca, who soon rewarded his fidelity with the gift of her hand and fortune.
The marriage contract, in the simple style of antiquity, recites the mutual love of Mohammed and Khadija; describes him as the most accomplished of the tribe of Koreish; and stipulates a dowry of twelve ounces of gold and twenty camels, which was supplied by the liberality of his uncle. (Decline and Fall of the Roman Empire)
Abu Talib read the khutba (sermon) of the marriage of Muhammad and Khadija, and his speech proves beyond any doubt that he was a monotheist. He began the speech in the “Muslim” style by offering thanks and praise to Allah for His mercy and for His countless gifts and blessings; and he concluded by invoking His mercy and blessings upon the newly-weds.
The marriage of Muhammad and Khadija was most successful. It was blessed with felicity unlimited for both husband and wife. Khadija dedicated her life to the service of her husband and of Islam. She spent all her vast wealth in strengthening Islam, and on the welfare of the Muslims.
Khadija had the same sense of mission as Muhammad had, and she was just as eageras he was to see Islam triumph over paganism. To her eagerness to see the triumph of Islam, she added commitment and power.
She freed her husband from the necessity of making a living, and thus enabled him to devote all his time to reflection and contemplation in preparation for the great work which lay ahead of him. This is a most significant contribution she made to the work of her husband as messenger of God. She was the fulcrum that he needed in all the years of preparation for the prophethood.
The marriage of Muhammad and Khadija was also blessed by the birth of their daughter, Fatima Zahra. Though the gifts which God bestowed upon them, were many, there was none that they treasured more than their daughter, Fatima Zahra. She was the “light of the eyes” of her father, and the future “Lady of Heaven.” The father and mother lavished their love on her, and she brought hope and happiness and the mercy and blessings of God with her into their home.