Wretched is the man who says: I forgot such and such a sura, or I forget such and such a verse, but he has been made to forget.
سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ بِئْسَمَا لِلرَّجُلِ أَنْ يَقُولَ نَسِيتُ سُورَةَ كَيْتَ وَكَيْتَ أَوْ نَسِيتُ آيَةَ كَيْتَ وَكَيْتَ بَلْ هُوَ نُسِّيَ