Marwan bin al-Hakam and Miswar bin Makhramah (may Allah be pleased with them both) told me that when the Messenger of Allah (peace and blessings be upon him) had the agreement for the fixed period written with Suhayl bin Amr (may Allah be pleased with him) on the day of Hudaybiyah, among the conditions Suhayl bin Amr (may Allah be pleased with him) laid down was: if any man of ours comes to you, even if he is on your religion, you must return him, and you will stand aside between us and him. Suhayl (may Allah be pleased with him) refused to make the agreement with the Messenger of Allah (peace and blessings be upon him) on anything other than that. The believers found this agreement hard to bear; they raised a clamour and spoke about it.
Suhayl (may Allah be pleased with him) said that the agreement would only be on this condition, so the Messenger of Allah (peace and blessings be upon him) had it written. Then the Messenger of Allah (peace and blessings be upon him) returned Abu Jandal (may Allah be pleased with him), the son of Suhayl (may Allah be pleased with him), to Suhayl (may Allah be pleased with him). If any Muslim man came to the Messenger of Allah (peace and blessings be upon him) during that period, he would return him. Then, when the believing women came as emigrants, among them was Umm Kulthum (may Allah be pleased with her), the daughter of Uqbah bin Abi Mu'ayt; she was free, and her family demanded her return. Then Allah revealed concerning those believing women whatever He revealed.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13970