It is narrated from Sayyidah Aishah (may Allah be pleased with her); she said: I was accused of what I was accused of while I was unaware of it. Meanwhile, the Prophet (peace and blessings be upon him) was sitting with me when he (peace and blessings be upon him) sat up straight, passed his hand over his face and said: "O Aishah, rejoice!" I said: "With the praise of Allah, not with praise of you." Then he (peace and blessings be upon him) recited these verses to me: "Indeed, those who accuse chaste, unaware, believing women" [Surah al-Nur: 23] and the verses that follow.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 19460