Sahih Bukhari Volume 9, Book 93, Hadith Number 635.

Narrated By ‘Aisha : (When the slanderers said what they said about her): I went to my bed knowing at that time that I was innocent and that Allah would reveal my innocence, but by Allah, I never thought that Allah would reveal in my favor a revelation which would be recited, for I considered myself too unimportant to be talked about by Allah in the Divine Revelation that was to be recited. So Allah revealed the ten Verses (of Surat-an-Nur). “Those who brought a false charge…” (24.11-20)