Sayyiduna Abdullah bin Abi Ahmad (may Allah be pleased with him) relates: Umm Kulthum bint Uqbah bin Abi Mu'ayt emigrated during the period of the truce. Her two brothers, Umarah and al-Walid, both sons of Uqbah, also set out and came to the Prophet (peace and blessings be upon him). They spoke with the Prophet (peace and blessings be upon him) about Umm Kulthum, asking that the Prophet (peace and blessings be upon him) return her to the two of them. So Allah Almighty annulled the covenant between the Prophet (peace and blessings be upon him) and the polytheists regarding women, and forbade that women be sent back to the polytheists. Then Allah Almighty revealed the verses concerning the examination.
Al-Tabarani recorded it; its chain contains a narrator, Abd al-Aziz bin Imran, who is da'if (weak).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب التفسير / 11413