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.
Sahih Muslim Book 6, Hadith 271
← Previous Hadith 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.

Sahih Muslim Book 6, Hadith 270 Next Hadith → Keep refreshing your knowledge of the Qur'an, for I swear by Him in Whose Hand is the life of Mahammad that it is more liable to escape than camels which are hobbled.

Sahih Muslim Book 6, Hadith 272