Forgetting the Qur'an After Having Memorized It
Question :
Does a person sin when he memorizes the Qur'an and later on forget it, being busy with life's affairs?
Answer:
The correct view is that there is no sin in that. Nevertheless, a Muslim should maintain what he memor- ized, and guard over it, so that he does not forget it. The Prophet ﷺ said: "Secure (your memorization of) the Qur'an, for it escapes more easily than a camel does from its fetter.
The most important responsibility regarding the Qur'an is that one should contemplate its meanings and apply its precepts.
The Qur'an is a proof for the person who applies it, a proof against the person who neglects it. The Prophet ﷺ said :
"The Qur'an is either a proof for you or a proof against you."
Recorded by Muslim in his Sahih from the long Hadith of Al- Harith Al-Ash'ari.
Source:
Ibn Baz
Fatawa Islamiyah, Vol. 7 Pages 84-85