His name was Abul-Aas Ibnur-Rabi (rta) from the clan of Abd Shams, a wealthy family. From his tribe Abul-Aas (rta) acquired the love of trade. People would entrust him with their money for investment. His aunt Khadijah (rta), the wife of the Prophet (sa), treated him as if he were one of her own children. When Zainab (rta), the daughter of the Prophet (sa), matured, she was given in marriage to Abul-Aas (rta).
Allah (swt) sent Muhammad (sa) as His messenger with the religion of Islam. His wife and daughters believed him, however, his son-in-law found it difficult to embrace Islam. The Quraish began plotting against the Prophet (sa) and went to Abul-Aas (rta), asking him to divorce his wife, so that the Prophet (sa) becomes preoccupied with the responsibility, but he refused to do so.
Other daughters of the Prophet (sa) married to the pagans were divorced and returned. The Prophet (sa) was not displeased. After the Prophet (sa) migrated to Madinah, the Quraish set out to confront Muslims at Badr. Abul-Aas (rta) was compelled to join them, although he did not hate Muslims. The battle resulted in terrible defeat for the Quraish, as their leadership was broken. Abul-Aas (rta) was among those, who were captured. The Prophet (sa) required each of the captives to pay a ransom for his release. Zainab (rta) sent a necklace as ransom money to rescue her husband. This necklace was given to her by her late mother Khadijah (rta). When the Prophet (sa) received the necklace of his beloved wife, Khadijah (rta), it greatly saddened him. Consequently, the Prophet (sa) made his son-in-law’s release contingent upon his commitment to send Zainab (rta) to Madinah as soon as possible.
Abul-Aas (rta) prepared to fulfill his promise as soon as he reached Makkah. He remained in Makkah for some time after the departure of his wife. He then went to Syria on business and on his way back to Makkah, a battalion of Muslim army surprised him. Abul-Aas (rta) fled. When night fell, he slipped into Madinah and asked his wife Zainab (rta) for her protection, and she gave it to him.
The next morning, during Fajr prayers, Zainab (rta) called out: “Hear me, everyone! I am Zainab, daughter of Muhammad. I have granted my protection to Abul-Aas, and I ask you to do the same.” The Prophet (sa) left the Masjid, went home, and told his daughter: “Treat him as an honoured guest, but you must know you are not his wife.” This was mainly because Allah (swt) had revealed verses instructing believers that they could not marry or stay married to pagans, unless they convert to Islam.
Abul-Aas’s (rta) captured property was returned to him. When he went to claim it, people asked him to embrace Islam, but he would not agree. Abul-Aas (rta) took the caravan from Madinah with all of its contents back to Makkah. When he arrived, he gave what he could to all those, who had entrusted him with their property for commerce, asking: “Listen all of you. Do I owe any of you any money, which I have not yet repaid? They replied: “No, may Allah (swt) reward you, for you have always been loyal and generous to us.” He said: “Then I have given everyone his due, and now I wish you to know that I bear witness that there is no God save Allah (swt), and that Muhammad (sa) is the messenger of Allah (swt).” Thus, he declared his conversion to Islam in Makkah.
He left Makkah with a contented heart and headed for Madinah. The Prophet (rta) welcomed him with all due honour and presented Zainab (rta) to him again, saying: “He spoke to me truthfully, and he kept the promise he made to me.”