حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا سُفْيَانُ، عَنْ مَنْصُورٍ، عَنْ أَبِي وَائِلٍ، عَنْ عَبْدِ اللَّهِ، قَالَ قَالَ النَّبِيُّ صلى الله عليه وسلم ‏"‏ مَا لأَحَدِهِمْ يَقُولُ نَسِيتُ آيَةَ كَيْتَ وَكَيْتَ‏.‏ بَلْ هُوَ نُسِّيَ ‏"‏‏.‏

Narrated `Abdullah: The Prophet (PBUH) said, "Why does anyone of the people say, 'I have forgotten such-and-such Verses (of the Qur'an)?' He, in fact, is caused (by Allah) to forget." Translation Not Available

Book Ref: Sahih Bukhari Book 66 Hadith 5039
Web Ref:  Sahih Bukhari Vol 6 Book 61 Hadith 559