Muhammad bin Ishaq narrated: The expedition of Banu al-Mustaliq took place in Sha'ban in the year 6 AH. On that expedition the Messenger of Allah (peace and blessings be upon him) set out taking Sayyidah Aishah with him; he (peace and blessings be upon him) had cast lots among his wives and her lot had come out. On that same expedition the people of the slander (ifk) said what they said, and Allah, the Mighty and Majestic, revealed her innocence.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19564
Shabab al-Usfuri narrated: It was in the year 6 AH; the expedition of Banu al-Mustaliq took place, and on that expedition the people of the slander (ifk) said what they said about Sayyidah Aishah, and the Qur'an was revealed in that connection: "Indeed, those who brought forth the slander", the verses.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19565