Hifdh

Ibn al-Jawzi said:

Al-Hasan, meaning ibn Abee Bakr an-Naysaabuuri, told us a story of a Faqeeh [i.e knowledgable person] who used to repeat his lesson many times whereupon a very old lady who happened to be in that same house said to the man, “By Allah even I have memorised it by now! [meaning that the man had repeated it so many times]” So the man said to her, “Recite it to me”, and so she did. After a few days the man came back to the lady and said; “Old lady! Recite to me that lesson [again]”, she replied to him, I did not memorize it. The man said:
I repeat the lesson [over and over again] so that I am not afflicted with that which afflicted you.

[Mutun Taalib al-‘Ilm by Shaykh ‘Abdul Muhsin al-Qaasim]

Moral of the story: Revision is a must for anything you learn, especially that which you memorize!

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