Sahih Bukhari
Virtues of the Quran
Volume: 006 / Book Number: 061 / Hadith Number: 558
Narrated Aisha:
Allah's Apostle heard a man reciting the Qur'an at night, and said, "May Allah bestow His Mercy on him, as he has reminded me of such-and-such Verses of such-and-such Suras, which I was caused to forget."