Abdullah reported Allah's Messenger (ﷺ) as saying:What a wretched person is he amongst them who says: I have forgotten such and such a verse. (He should instead of using this expression say): I have been made to forget it. Try to remember the Qur'an for it is more apt to escape from men's minds than a hobbled camel

Abdullah is reported to have said:Keep refreshing your knowledge of the sacred books (or always renew your knowledge of these sacred books) and sometimes he would mention the Qur'an for it is more apt to escape from men's minds than animals which are hobbled, and the Messenger of Allah (ﷺ) said: None of you should say: I forgot such and such a verse, but he has been made to forget

Ibn Mas'ud reported Allah's Messenger (ﷺ) as saying: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