The Prophet ﷺ 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." (Using translation from Bukhārī 5039)
قَالَ رَسُولُ اللهِ ﷺ بِئْسَمَا لَأَحَدِهِمْ أَنْ يَقُولَ نَسِيتُ آيَةَ كَيْتَ وَكَيْتَ بَلْ هُوَ نُسِّيَ