Khadija's grandfather, Asad ibn Abd-al-Uzza, was the progenitor^{[clarification needed]} of the Asad clan^[2] of the Quraysh tribe in Mecca. Her father, Khuwaylid ibn Asad, was a merchant.^[2] According to some traditions, he died c. 585 in the Sacrilegious War, but according to others, he was still alive when Khadija married Muhammad in 595.^[3][4] His sister, Umm Habib bint Asad, was the matrilineal great-grandmother of Muhammad.^[5]Khadija's mother, Fatima bint Za'idah, who died around 575,^{[citation needed]} was a member of the Amir ibn Luayy clan of the Quraysh^[6] and a third cousin of Muhammad's mother.^[7][8]

Khadija married three times and had children from all her marriages. While the order of her marriages is debated, it is generally believed that she first married Abu Hala Malak ibn Nabash ibn Zarrara ibn at-Tamimi and second 'Atiq ibn 'A'idh ibn 'Abdullah Al-Makhzumi.^[9] To her first husband she bore two sons, who were both given what were usually feminine names,^[10] Hala and Hind. He died before his business became a success.^[11] To husband Atiq, Khadija bore a daughter named Hindah. This marriage also left Khadija as a widow.^[12]

Khadija became a very successful merchant. It is said that when the Quraysh's tradecaravans gathered to embark upon their summer journey to Syria or winter journey toYemen, Khadija's caravan equalled the caravans of all other traders of the Quraysh put together.^[13] She was known by the by-names Ameerat-Quraysh ("Princess of Quraysh"), al-Tahira ("The Pure One") and Khadija Al-Kubra (Khadija "the Great").^[14]It is said that she fed and clothed the poor, assisted her relatives financially and provided marriage portions for poor relations.^[14] Khadija was said to have neither believed in nor worshipped idols,^{[citation needed]} which was atypical for pre-Islamic Arabianculture. According to other sources, however, she kept an idol of Al-‘Uzzá in her house.^[15]

Khadija did not travel with her trade caravans; she employed others to trade on her behalf for a commission. In 595 Khadija needed an agent for a transaction in Syria. Abu Talib ibn 'Abd al-Muttalib recommended her distant cousin Muhammad ibn Abdullah. The experience that Muhammad held working with caravans in his uncle Abu Talib's family business had earned him the honorific titles Al-Sadiq ("the Truthful") and Al-Amin ("the Trustworthy" or "Honest").^[16] Khadija hired Muhammad, who was then 25 years old, sending word through her kinsman Khazimah ibn Hakim^{[citation needed]} that she would pay double her usual commission.^[17]

She sent one of her servants, Maysarah, to assist him. Upon returning, Maysarah gave accounts of the honorable way that Muhammad had conducted his business, with the result that he brought back twice as much profit as Khadija had expected. Maysarah also relayed that on the return journey, Muhammad had stopped to rest under a tree. A passing monk, Nestora, informed Maysarah that, "None but a prophet ever sat beneath this tree."^[18] Maysarah also claimed that while he stood near Muhammad as he slept, he had seen two angels standing above Muhammad creating a cloud to protect him from the heat and glare of the sun.^[11]

Khadija then consulted her cousin Waraqah ibn Nawfal ibn Asad ibn 'Abdu'l-'Uzza.^[18] Waraqah said that if what Maysarah had seen was true, then Muhammad was in fact the prophet of the people who was already expected. It is also said Khadijah had a dream in which the sun descended from the sky into her courtyard, fully illuminating her home.^[11] Her cousin Waraqah told her not to be alarmed, for the sun was an indication that the Prophet would grace her home.^[11] At this, Khadija considered proposing marriage to her agent.^[19] Many wealthy Quraysh men had already asked for her hand in marriage,^[11] but all had been refused.^[20]

Khadija entrusted a friend named Nafisa to approach Muhammad and ask if he would consider marrying.^[21] At first Muhammad was hesitant because he had no money to support a wife. Nafisa then asked if he would consider marriage to a woman who had the means to provide for herself.^[22] Muhammad agreed to meet with Khadija, and after this meeting they consulted their respective uncles. The uncles agreed to the marriage, and Muhammad's uncles accompanied him to make a formal proposal to Khadija.^[18] It is disputed whether it was only Hamza ibn Abdul-Muttalib or only Abu Talib or both who accompanied Muhammad on this errand.^[12] Khadija's uncle accepted the proposal, and the marriage took place.

Muhammad and Khadija were married monogamously for twenty-five years. This monogamous marriage contrasts with Muhammad's later practice of polygyny after Khadija's death. Muhammad's youngest wife, Aisha, was to be jealous of the affection and loyalty that Muhammad maintained for Khadija even after her death.^[23]

Muhammad and Khadija had six children.^[11] (Sources disagree about number of children; Al-Tabari names eight, but most sources only identify six).^[9]

Their first son was Qasim, who died before his second birthday^[24] (hence Muhammad's kunya Abu Qasim). Khadija then gave birth to their daughters Zaynab, Ruqayyah, Umm Kulthum and Fatima; and lastly to their son Abd-Allah. Abd-Allahwas known as at-Tayyib ("the Good") and at-Tahir ("the Pure") because he was born after Muhammad declared himself a prophet. Abdullah also died in childhood.^[11]

Two other children also lived in Khadija's household.