The Treaty Clause
The Treaty of Hudaybiyya (6 AH / 628 CE), agreed between the Prophet and the Quraysh, included a clause: any person from Quraysh who went to the Muslims without his guardian’s permission must be returned to Mecca. This clause applied to those who had been prevented from going with the Prophet’s expedition and came subsequently to Medina seeking refuge.
Under this clause, Muslim men who fled to Medina were returned — a concession that troubled the Companions but which the Prophet accepted.
Umm Kulthum’s Flight
After the treaty, Umm Kulthum bint Uqba fled Mecca for Medina. Her brothers came to the Prophet demanding her return under the treaty clause. At this point, the Quran intervened with verse 60:10: “O you who have believed, when believing women come to you as emigrants, examine them. God is most knowing as to their faith. And if you know them to be believers, then do not return them to the disbelievers; they are not lawful [wives] for them, nor are they lawful [husbands] for them.”
The divine ruling: believing women who emigrate to the Muslims are not to be returned to the disbelievers. The treaty clause, as it applied to women, was modified.
The Practical Resolution
The Prophet informed the Qurayshi delegation that the verse had come, exempting believing women from the return clause. He offered to pay compensation for the women who had come — the price they represented in marriage contracts — which the Quraysh accepted.
See also: Seerah Zaynab Bint Khuzayma, Seerah Umm Sulaym, Seerah Umm Habiba, Seerah Zayd Ibn Haritha, Fath Mecca